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diff --git a/man/systemd.network.xml b/man/systemd.network.xml new file mode 100644 index 0000000..e1c050f --- /dev/null +++ b/man/systemd.network.xml @@ -0,0 +1,4940 @@ +<?xml version='1.0'?> +<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" + "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> +<!-- SPDX-License-Identifier: LGPL-2.1-or-later --> + +<refentry id="systemd.network" conditional='ENABLE_NETWORKD' + xmlns:xi="http://www.w3.org/2001/XInclude"> + + <refentryinfo> + <title>systemd.network</title> + <productname>systemd</productname> + </refentryinfo> + + <refmeta> + <refentrytitle>systemd.network</refentrytitle> + <manvolnum>5</manvolnum> + </refmeta> + + <refnamediv> + <refname>systemd.network</refname> + <refpurpose>Network configuration</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <para><filename><replaceable>network</replaceable>.network</filename></para> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para>A plain ini-style text file that encodes network configuration for matching network + interfaces, used by + <citerefentry><refentrytitle>systemd-networkd</refentrytitle><manvolnum>8</manvolnum></citerefentry>. + See <citerefentry><refentrytitle>systemd.syntax</refentrytitle><manvolnum>7</manvolnum></citerefentry> + for a general description of the syntax.</para> + + <para>The main network file must have the extension <filename>.network</filename>; other + extensions are ignored. Networks are applied to links whenever the links appear.</para> + + <para>The <filename>.network</filename> files are read from the files located in the system network + directories <filename>/usr/lib/systemd/network</filename> and + <filename>/usr/local/lib/systemd/network</filename>, the volatile runtime network directory + <filename>/run/systemd/network</filename> and the local administration network directory + <filename>/etc/systemd/network</filename>. All configuration files are collectively sorted and + processed in alphanumeric order, regardless of the directories in which they live. However, files + with identical filenames replace each other. It is recommended that each filename is prefixed with + a number (e.g. <filename>10-eth0.network</filename>). Otherwise, the default + <filename>.network</filename> files or those generated by + <citerefentry><refentrytitle>systemd-network-generator.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> + may take precedence over user configured files. Files in <filename>/etc/</filename> have the highest + priority, files in <filename>/run/</filename> take precedence over files with the same name under + <filename>/usr/</filename>. This can be used to override a system-supplied configuration file with + a local file if needed. As a special case, an empty file (file size 0) or symlink with the same + name pointing to <filename>/dev/null</filename> disables the configuration file entirely (it is + "masked").</para> + + <para>Along with the network file <filename>foo.network</filename>, a "drop-in" directory + <filename>foo.network.d/</filename> may exist. All files with the suffix + <literal>.conf</literal> from this directory will be merged in the alphanumeric order and parsed + after the main file itself has been parsed. This is useful to alter or add configuration settings, + without having to modify the main configuration file. Each drop-in file must have appropriate + section headers.</para> + + <para>In addition to <filename>/etc/systemd/network</filename>, drop-in <literal>.d</literal> + directories can be placed in <filename>/usr/lib/systemd/network</filename> or + <filename>/run/systemd/network</filename> directories. Drop-in files in + <filename>/etc/</filename> take precedence over those in <filename>/run/</filename> which in turn + take precedence over those in <filename>/usr/lib/</filename>. Drop-in files under any of these + directories take precedence over the main network file wherever located.</para> + </refsect1> + + <refsect1> + <title>[Match] Section Options</title> + + <para>The network file contains a [Match] section, which determines if a given network file may + be applied to a given interface; and a [Network] section specifying how the interface should be + configured. The first (in alphanumeric order) of the network files that matches a given interface + is applied, all later files are ignored, even if they match as well.</para> + + <para>A network file is said to match a network interface if all matches specified by the [Match] + section are satisfied. When a network file does not contain valid settings in [Match] section, then + the file will match all interfaces and <command>systemd-networkd</command> warns about that. Hint: + to avoid the warning and to make it clear that all interfaces shall be matched, add the following: + <programlisting>Name=*</programlisting> The following keys are accepted:</para> + + <variablelist class='network-directives'> + <xi:include href="systemd.link.xml" xpointer="mac-address" /> + <xi:include href="systemd.link.xml" xpointer="permanent-mac-address" /> + <xi:include href="systemd.link.xml" xpointer="path" /> + <xi:include href="systemd.link.xml" xpointer="driver" /> + <xi:include href="systemd.link.xml" xpointer="type" /> + <xi:include href="systemd.link.xml" xpointer="kind" /> + <xi:include href="systemd.link.xml" xpointer="property" /> + + <varlistentry> + <term><varname>Name=</varname></term> + <listitem> + <para>A whitespace-separated list of shell-style globs matching the device name, as exposed + by the udev property <literal>INTERFACE</literal>, or device's alternative names. If the + list is prefixed with a "!", the test is inverted.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>WLANInterfaceType=</varname></term> + <listitem> + <para>A whitespace-separated list of wireless network type. Supported values are + <literal>ad-hoc</literal>, <literal>station</literal>, <literal>ap</literal>, + <literal>ap-vlan</literal>, <literal>wds</literal>, <literal>monitor</literal>, + <literal>mesh-point</literal>, <literal>p2p-client</literal>, <literal>p2p-go</literal>, + <literal>p2p-device</literal>, <literal>ocb</literal>, and <literal>nan</literal>. If the + list is prefixed with a "!", the test is inverted. </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>SSID=</varname></term> + <listitem> + <para>A whitespace-separated list of shell-style globs matching the SSID of the currently + connected wireless LAN. If the list is prefixed with a "!", the test is inverted.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>BSSID=</varname></term> + <listitem> + <para>A whitespace-separated list of hardware address of the currently connected wireless + LAN. Use full colon-, hyphen- or dot-delimited hexadecimal. See the example in + <varname>MACAddress=</varname>. This option may appear more than once, in which case the + lists are merged. If the empty string is assigned to this option, the list is reset.</para> + </listitem> + </varlistentry> + + <xi:include href="systemd.link.xml" xpointer="host" /> + <xi:include href="systemd.link.xml" xpointer="virtualization" /> + <xi:include href="systemd.link.xml" xpointer="kernel-command-line" /> + <xi:include href="systemd.link.xml" xpointer="kernel-version" /> + <xi:include href="systemd.link.xml" xpointer="credential" /> + <xi:include href="systemd.link.xml" xpointer="architecture" /> + <xi:include href="systemd.link.xml" xpointer="firmware" /> + </variablelist> + </refsect1> + + <refsect1> + <title>[Link] Section Options</title> + + <para>The [Link] section accepts the following keys:</para> + + <variablelist class='network-directives'> + <varlistentry> + <term><varname>MACAddress=</varname></term> + <listitem> + <para>The hardware address to set for the device.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>MTUBytes=</varname></term> + <listitem> + <para>The maximum transmission unit in bytes to set for the device. The usual suffixes K, M, + G, are supported and are understood to the base of 1024.</para> + <para>Note that if IPv6 is enabled on the interface, and the MTU is chosen below 1280 (the + minimum MTU for IPv6) it will automatically be increased to this value.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>ARP=</varname></term> + <listitem> + <para>Takes a boolean. If set to true, the ARP (low-level Address Resolution Protocol) + for this interface is enabled. When unset, the kernel's default will be used.</para> + <para> For example, disabling ARP is useful when creating multiple MACVLAN or VLAN virtual + interfaces atop a single lower-level physical interface, which will then only serve as a + link/"bridge" device aggregating traffic to the same physical link and not participate in + the network otherwise. Defaults to unset.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Multicast=</varname></term> + <listitem> + <para>Takes a boolean. If set to true, the multicast flag on the device is enabled. Defaults + to unset.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>AllMulticast=</varname></term> + <listitem> + <para>Takes a boolean. If set to true, the driver retrieves all multicast packets from the + network. This happens when multicast routing is enabled. Defaults to unset.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Promiscuous=</varname></term> + <listitem> + <para>Takes a boolean. If set to true, promiscuous mode of the interface is enabled. Defaults + to unset.</para> + <para>If this is set to false for the underlying link of a <literal>passthru</literal> mode + MACVLAN/MACVTAP, the virtual interface will be created with the <literal>nopromisc</literal> + flag set.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Unmanaged=</varname></term> + <listitem> + <para>Takes a boolean. When <literal>yes</literal>, no attempts are made to bring up or + configure matching links, equivalent to when there are no matching network files. Defaults to + <literal>no</literal>.</para> + <para>This is useful for preventing later matching network files from interfering with + certain interfaces that are fully controlled by other applications.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Group=</varname></term> + <listitem> + <para>Link groups are similar to port ranges found in managed switches. When network + interfaces are added to a numbered group, operations on all the interfaces from that group + can be performed at once. Takes an unsigned integer in the range 0…2147483647. Defaults to + unset.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>RequiredForOnline=</varname></term> + <listitem> + <para>Takes a boolean or a minimum operational state and an optional maximum operational + state. Please see + <citerefentry><refentrytitle>networkctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> + for possible operational states. When <literal>yes</literal>, the network is deemed required + when determining whether the system is online (including when running + <command>systemd-networkd-wait-online</command>). When <literal>no</literal>, the network is + ignored when determining the online state. When a minimum operational state and an optional + maximum operational state are set, <literal>yes</literal> is implied, and this controls the + minimum and maximum operational state required for the network interface to be considered + online.</para> + + <para>Defaults to <literal>yes</literal> when <varname>ActivationPolicy=</varname> is not + set, or set to <literal>up</literal>, <literal>always-up</literal>, or + <literal>bound</literal>. Defaults to <literal>no</literal> when + <varname>ActivationPolicy=</varname> is set to <literal>manual</literal> or + <literal>down</literal>. This is forced to <literal>no</literal> when + <varname>ActivationPolicy=</varname> is set to <literal>always-down</literal>.</para> + + <para>The network will be brought up normally (as configured by + <varname>ActivationPolicy=</varname>), but in the event that there is no address being + assigned by DHCP or the cable is not plugged in, the link will simply remain offline and be + skipped automatically by <command>systemd-networkd-wait-online</command> if + <literal>RequiredForOnline=no</literal>.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>RequiredFamilyForOnline=</varname></term> + <listitem> + <para>Takes an address family. When specified, an IP address in the given family is deemed + required when determining whether the link is online (including when running + <command>systemd-networkd-wait-online</command>). Takes one of <literal>ipv4</literal>, + <literal>ipv6</literal>, <literal>both</literal>, or <literal>any</literal>. Defaults to + <literal>any</literal>. Note that this option has no effect if + <literal>RequiredForOnline=no</literal>, or if <literal>RequiredForOnline=</literal> + specifies a minimum operational state below <literal>degraded</literal>.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>ActivationPolicy=</varname></term> + <listitem> + <para>Specifies the policy for <command>systemd-networkd</command> managing the link + administrative state. Specifically, this controls how <command>systemd-networkd</command> + changes the network device's <literal>IFF_UP</literal> flag, which is sometimes + controlled by system administrators by running e.g., + <command>ip link set dev eth0 up</command> or <command>ip link set dev eth0 down</command>, + and can also be changed with <command>networkctl up eth0</command> or + <command>networkctl down eth0</command>.</para> + + <para>Takes one of <literal>up</literal>, <literal>always-up</literal>, + <literal>manual</literal>, <literal>always-down</literal>, <literal>down</literal>, + or <literal>bound</literal>. When <literal>manual</literal>, + <command>systemd-networkd</command> will not change the link's admin state automatically; + the system administrator must bring the interface up or down manually, as desired. When + <literal>up</literal> (the default) or <literal>always-up</literal>, or + <literal>down</literal> or <literal>always-down</literal>, + <command>systemd-networkd</command> will set the link up or down, respectively, when the + interface is (re)configured. When <literal>always-up</literal> or + <literal>always-down</literal>, <command>systemd-networkd</command> will set the link up or + down, respectively, any time <command>systemd-networkd</command> detects a change in the + administrative state. When <varname>BindCarrier=</varname> is also set, this is automatically + set to <literal>bound</literal> and any other value is ignored.</para> + + <para>When the policy is set to <literal>down</literal> or <literal>manual</literal>, the + default value of <varname>RequiredForOnline=</varname> is <literal>no</literal>. When the + policy is set to <literal>always-down</literal>, the value of + <varname>RequiredForOnline=</varname> forced to <literal>no</literal>.</para> + + <para>The administrative state is not the same as the carrier state, so using + <literal>always-up</literal> does not mean the link will never lose carrier. The link carrier + depends on both the administrative state as well as the network device's physical connection. + However, to avoid reconfiguration failures, when using <literal>always-up</literal>, + <varname>IgnoreCarrierLoss=</varname> is forced to true.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <xi:include href="systemd.link.xml" xpointer="sr-iov" /> + + <refsect1> + <title>[Network] Section Options</title> + + <para>The [Network] section accepts the following keys:</para> + + <variablelist class='network-directives'> + <varlistentry> + <term><varname>Description=</varname></term> + <listitem> + <para>A description of the device. This is only used for presentation purposes.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>DHCP=</varname></term> + <listitem> + <para>Enables DHCPv4 and/or DHCPv6 client support. Accepts <literal>yes</literal>, + <literal>no</literal>, <literal>ipv4</literal>, or <literal>ipv6</literal>. Defaults to + <literal>no</literal>.</para> + + <para>Note that DHCPv6 will by default be triggered by Router Advertisements, if reception is + enabled, regardless of this parameter. By explicitly enabling DHCPv6 support here, the DHCPv6 + client will be started in the mode specified by the <varname>WithoutRA=</varname> setting in the + [DHCPv6] section, regardless of the presence of routers on the link, or what flags the routers + pass. See <varname>IPv6AcceptRA=</varname>.</para> + + <para>Furthermore, note that by default the domain name specified through DHCP is not used + for name resolution. See option <option>UseDomains=</option> below.</para> + + <para>See the [DHCPv4] or [DHCPv6] sections below for further configuration options for the + DHCP client support.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>DHCPServer=</varname></term> + <listitem> + <para>Takes a boolean. If set to <literal>yes</literal>, DHCPv4 server will be started. + Defaults to <literal>no</literal>. Further settings for the DHCP server may be set in the + [DHCPServer] section described below.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>LinkLocalAddressing=</varname></term> + <listitem> + <para>Enables link-local address autoconfiguration. Accepts <option>yes</option>, + <option>no</option>, <option>ipv4</option>, and <option>ipv6</option>. An IPv6 link-local + address is configured when <option>yes</option> or <option>ipv6</option>. An IPv4 link-local + address is configured when <option>yes</option> or <option>ipv4</option> and when DHCPv4 + autoconfiguration has been unsuccessful for some time. (IPv4 link-local address + autoconfiguration will usually happen in parallel with repeated attempts to acquire a DHCPv4 + lease).</para> + + <para>Defaults to <option>no</option> when <varname>KeepMaster=</varname> or + <varname>Bridge=</varname> is set or when the specified + <varname>MACVLAN=</varname>/<varname>MACVTAP=</varname> has <varname>Mode=passthru</varname>, + or <option>ipv6</option> otherwise.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>IPv6LinkLocalAddressGenerationMode=</varname></term> + <listitem> + <para>Specifies how IPv6 link-local address is generated. Takes one of + <literal>eui64</literal>, <literal>none</literal>, <literal>stable-privacy</literal> and + <literal>random</literal>. When unset, <literal>stable-privacy</literal> is used if + <varname>IPv6StableSecretAddress=</varname> is specified, and if not, + <literal>eui64</literal> is used. Note that if <varname>LinkLocalAddressing=</varname> is + <literal>no</literal> or <literal>ipv4</literal>, then + <varname>IPv6LinkLocalAddressGenerationMode=</varname> will be ignored. Also, even if + <varname>LinkLocalAddressing=</varname> is <literal>yes</literal> or <literal>ipv6</literal>, + setting <varname>IPv6LinkLocalAddressGenerationMode=none</varname> + disables to configure an IPv6 link-local address.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>IPv6StableSecretAddress=</varname></term> + <listitem> + <para>Takes an IPv6 address. The specified address will be used as a stable secret for + generating IPv6 link-local address. If this setting is specified, and + <varname>IPv6LinkLocalAddressGenerationMode=</varname> is unset, then + <varname>IPv6LinkLocalAddressGenerationMode=stable-privacy</varname> is implied. + If this setting is not specified, and <literal>stable-privacy</literal> is set to + <varname>IPv6LinkLocalAddressGenerationMode=</varname>, + then a stable secret address will be generated from the local machine ID and the interface + name.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>IPv4LLStartAddress=</varname></term> + <listitem> + <para>Specifies the first IPv4 link-local address to try. Takes an IPv4 address for example + 169.254.1.2, from the link-local address range: 169.254.0.0/16 except for 169.254.0.0/24 and + 169.254.255.0/24. This setting may be useful if the device should always have the same address + as long as there is no address conflict. When unset, a random address will be automatically + selected. Defaults to unset.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>IPv4LLRoute=</varname></term> + <listitem> + <para>Takes a boolean. If set to true, sets up the route needed for non-IPv4LL hosts to + communicate with IPv4LL-only hosts. Defaults to false.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>DefaultRouteOnDevice=</varname></term> + <listitem> + <para>Takes a boolean. If set to true, sets up the IPv4 default route bound to the interface. + Defaults to false. This is useful when creating routes on point-to-point interfaces. This is + equivalent to e.g. the following, + <programlisting>ip route add default dev veth99</programlisting> + or, + <programlisting>[Route] +Gateway=0.0.0.0</programlisting></para> + <para>Currently, there are no way to specify e.g., the table for the route configured by this + setting. To configure the default route with such an additional property, please use the + following instead: + <programlisting>[Route] +Gateway=0.0.0.0 +Table=1234</programlisting></para> + <para>If you'd like to create an IPv6 default route bound to the interface, please use the + following: + <programlisting>[Route] +Gateway=:: +Table=1234</programlisting></para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>LLMNR=</varname></term> + <listitem> + <para>Takes a boolean or <literal>resolve</literal>. When true, enables + <ulink url="https://tools.ietf.org/html/rfc4795">Link-Local Multicast Name Resolution</ulink> + on the link. When set to <literal>resolve</literal>, only resolution is enabled, but not host + registration and announcement. Defaults to true. This setting is read by + <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>MulticastDNS=</varname></term> + <listitem> + <para>Takes a boolean or <literal>resolve</literal>. When true, enables + <ulink url="https://tools.ietf.org/html/rfc6762">Multicast DNS</ulink> support on the link. + When set to <literal>resolve</literal>, only resolution is enabled, but not host or service + registration and announcement. Defaults to false. This setting is read by + <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>DNSOverTLS=</varname></term> + <listitem> + <para>Takes a boolean or <literal>opportunistic</literal>. When true, enables + <ulink url="https://tools.ietf.org/html/rfc7858">DNS-over-TLS</ulink> support on the link. + When set to <literal>opportunistic</literal>, compatibility with non-DNS-over-TLS servers is + increased, by automatically turning off DNS-over-TLS servers in this case. This option + defines a per-interface setting for + <citerefentry><refentrytitle>resolved.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>'s + global <varname>DNSOverTLS=</varname> option. Defaults to unset, and the global setting will + be used. This setting is read by + <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>DNSSEC=</varname></term> + <listitem> + <para>Takes a boolean or <literal>allow-downgrade</literal>. When true, enables + <ulink url="https://tools.ietf.org/html/rfc4033">DNSSEC</ulink> DNS validation support on the + link. When set to <literal>allow-downgrade</literal>, compatibility with non-DNSSEC capable + networks is increased, by automatically turning off DNSSEC in this case. This option defines + a per-interface setting for + <citerefentry><refentrytitle>resolved.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>'s + global <varname>DNSSEC=</varname> option. Defaults to unset, and the global setting will be + used. This setting is read by + <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>DNSSECNegativeTrustAnchors=</varname></term> + <listitem> + <para>A space-separated list of DNSSEC negative trust anchor domains. If specified and DNSSEC + is enabled, look-ups done via the interface's DNS server will be subject to the list of + negative trust anchors, and not require authentication for the specified domains, or anything + below it. Use this to disable DNSSEC authentication for specific private domains, that cannot + be proven valid using the Internet DNS hierarchy. Defaults to the empty list. This setting is + read by + <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>LLDP=</varname></term> + <listitem> + <para>Controls support for Ethernet LLDP packet reception. LLDP is a link-layer protocol + commonly implemented on professional routers and bridges which announces which physical port + a system is connected to, as well as other related data. Accepts a boolean or the special + value <literal>routers-only</literal>. When true, incoming LLDP packets are accepted and a + database of all LLDP neighbors maintained. If <literal>routers-only</literal> is set only + LLDP data of various types of routers is collected and LLDP data about other types of devices + ignored (such as stations, telephones and others). If false, LLDP reception is disabled. + Defaults to <literal>routers-only</literal>. Use + <citerefentry><refentrytitle>networkctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> + to query the collected neighbor data. LLDP is only available on Ethernet links. See + <varname>EmitLLDP=</varname> below for enabling LLDP packet emission from the local system. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>EmitLLDP=</varname></term> + <listitem> + <para>Controls support for Ethernet LLDP packet emission. Accepts a boolean parameter or the + special values <literal>nearest-bridge</literal>, <literal>non-tpmr-bridge</literal> and + <literal>customer-bridge</literal>. Defaults to false, which turns off LLDP packet emission. + If not false, a short LLDP packet with information about the local system is sent out in + regular intervals on the link. The LLDP packet will contain information about the local + hostname, the local machine ID (as stored in + <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>) + and the local interface name, as well as the pretty hostname of the system (as set in + <citerefentry><refentrytitle>machine-info</refentrytitle><manvolnum>5</manvolnum></citerefentry>). + LLDP emission is only available on Ethernet links. Note that this setting passes data + suitable for identification of host to the network and should thus not be enabled on + untrusted networks, where such identification data should not be made available. Use this + option to permit other systems to identify on which interfaces they are connected to this + system. The three special values control propagation of the LLDP packets. The + <literal>nearest-bridge</literal> setting permits propagation only to the nearest connected + bridge, <literal>non-tpmr-bridge</literal> permits propagation across Two-Port MAC Relays, + but not any other bridges, and <literal>customer-bridge</literal> permits propagation until + a customer bridge is reached. For details about these concepts, see + <ulink url="https://standards.ieee.org/findstds/standard/802.1AB-2016.html">IEEE 802.1AB-2016</ulink>. + Note that configuring this setting to true is equivalent to + <literal>nearest-bridge</literal>, the recommended and most restricted level of propagation. + See <varname>LLDP=</varname> above for an option to enable LLDP reception.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>BindCarrier=</varname></term> + <listitem> + <para>A link name or a list of link names. When set, controls the behavior of the current + link. When all links in the list are in an operational down state, the current link is + brought down. When at least one link has carrier, the current interface is brought up.</para> + + <para>This forces <varname>ActivationPolicy=</varname> to be set to <literal>bound</literal>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Address=</varname></term> + <listitem> + <para>A static IPv4 or IPv6 address and its prefix length, separated by a + <literal>/</literal> character. Specify this key more than once to configure several + addresses. The format of the address must be as described in + <citerefentry project='man-pages'><refentrytitle>inet_pton</refentrytitle><manvolnum>3</manvolnum></citerefentry>. + This is a short-hand for an [Address] section only containing an Address key (see below). + This option may be specified more than once.</para> + + <para>If the specified address is <literal>0.0.0.0</literal> (for IPv4) or + <literal>::</literal> (for IPv6), a new address range of the requested size is automatically + allocated from a system-wide pool of unused ranges. Note that the prefix length must be equal + or larger than 8 for IPv4, and 64 for IPv6. The allocated range is checked against all + current network interfaces and all known network configuration files to avoid address range + conflicts. The default system-wide pool consists of 192.168.0.0/16, 172.16.0.0/12 and + 10.0.0.0/8 for IPv4, and fd00::/8 for IPv6. This functionality is useful to manage a large + number of dynamically created network interfaces with the same network configuration and + automatic address range assignment.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Gateway=</varname></term> + <listitem> + <para>The gateway address, which must be in the format described in + <citerefentry project='man-pages'><refentrytitle>inet_pton</refentrytitle><manvolnum>3</manvolnum></citerefentry>. + This is a short-hand for a [Route] section only containing a <varname>Gateway=</varname> key. + This option may be specified more than once.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>DNS=</varname></term> + <listitem> + <para>A DNS server address, which must be in the format described in + <citerefentry project='man-pages'><refentrytitle>inet_pton</refentrytitle><manvolnum>3</manvolnum></citerefentry>. + This option may be specified more than once. Each address can optionally take a port number + separated with <literal>:</literal>, a network interface name or index separated with + <literal>%</literal>, and a Server Name Indication (SNI) separated with <literal>#</literal>. + When IPv6 address is specified with a port number, then the address must be in the square + brackets. That is, the acceptable full formats are + <literal>111.222.333.444:9953%ifname#example.com</literal> for IPv4 and + <literal>[1111:2222::3333]:9953%ifname#example.com</literal> for IPv6. If an empty string is + assigned, then the all previous assignments are cleared. This setting is read by + <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Domains=</varname></term> + <listitem> + <para>A whitespace-separated list of domains which should be resolved using the DNS servers + on this link. Each item in the list should be a domain name, optionally prefixed with a tilde + (<literal>~</literal>). The domains with the prefix are called "routing-only domains". The + domains without the prefix are called "search domains" and are first used as search suffixes + for extending single-label hostnames (hostnames containing no dots) to become fully qualified + domain names (FQDNs). If a single-label hostname is resolved on this interface, each of the + specified search domains are appended to it in turn, converting it into a fully qualified + domain name, until one of them may be successfully resolved.</para> + + <para>Both "search" and "routing-only" domains are used for routing of DNS queries: look-ups + for hostnames ending in those domains (hence also single label names, if any "search domains" + are listed), are routed to the DNS servers configured for this interface. The domain routing + logic is particularly useful on multi-homed hosts with DNS servers serving particular private + DNS zones on each interface.</para> + + <para>The "routing-only" domain <literal>~.</literal> (the tilde indicating definition of a + routing domain, the dot referring to the DNS root domain which is the implied suffix of all + valid DNS names) has special effect. It causes all DNS traffic which does not match another + configured domain routing entry to be routed to DNS servers specified for this interface. + This setting is useful to prefer a certain set of DNS servers if a link on which they are + connected is available.</para> + + <para>This setting is read by + <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>. + "Search domains" correspond to the <varname>domain</varname> and <varname>search</varname> + entries in + <citerefentry project='man-pages'><refentrytitle>resolv.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>. + Domain name routing has no equivalent in the traditional glibc API, which has no concept of + domain name servers limited to a specific link.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>DNSDefaultRoute=</varname></term> + <listitem> + <para>Takes a boolean argument. If true, this link's configured DNS servers are used for + resolving domain names that do not match any link's configured <varname>Domains=</varname> + setting. If false, this link's configured DNS servers are never used for such domains, and + are exclusively used for resolving names that match at least one of the domains configured on + this link. If not specified defaults to an automatic mode: queries not matching any link's + configured domains will be routed to this link if it has no routing-only domains configured. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>NTP=</varname></term> + <listitem> + <para>An NTP server address (either an IP address, or a hostname). This option may be + specified more than once. This setting is read by + <citerefentry><refentrytitle>systemd-timesyncd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>IPForward=</varname></term> + <listitem> + <para>Configures IP packet forwarding for the system. If enabled, incoming packets on any + network interface will be forwarded to any other interfaces according to the routing table. + Takes a boolean, or the values <literal>ipv4</literal> or <literal>ipv6</literal>, which only + enable IP packet forwarding for the specified address family. This controls the + <filename>net.ipv4.ip_forward</filename> and <filename>net.ipv6.conf.all.forwarding</filename> + sysctl options of the network interface (see + <ulink url="https://docs.kernel.org/networking/ip-sysctl.html">IP Sysctl</ulink> + for details about sysctl options). Defaults to <literal>no</literal>.</para> + + <para>Note: this setting controls a global kernel option, and does so one way only: if a + network that has this setting enabled is set up the global setting is turned on. However, + it is never turned off again, even after all networks with this setting enabled are shut + down again.</para> + + <para>To allow IP packet forwarding only between specific network interfaces use a firewall. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>IPMasquerade=</varname></term> + <listitem> + <para>Configures IP masquerading for the network interface. If enabled, packets forwarded + from the network interface will be appear as coming from the local host. Takes one of + <literal>ipv4</literal>, <literal>ipv6</literal>, <literal>both</literal>, or + <literal>no</literal>. Defaults to <literal>no</literal>. If enabled, this automatically sets + <varname>IPForward=</varname> to one of <literal>ipv4</literal>, <literal>ipv6</literal> or + <literal>yes</literal>.</para> + <para>Note. Any positive boolean values such as <literal>yes</literal> or + <literal>true</literal> are now deprecated. Please use one of the values in the above.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>IPv6PrivacyExtensions=</varname></term> + <listitem> + <para>Configures use of stateless temporary addresses that change over time (see + <ulink url="https://tools.ietf.org/html/rfc4941">RFC 4941</ulink>, + Privacy Extensions for Stateless Address Autoconfiguration in IPv6). Takes a boolean or the + special values <literal>prefer-public</literal> and <literal>kernel</literal>. When true, + enables the privacy extensions and prefers temporary addresses over public addresses. When + <literal>prefer-public</literal>, enables the privacy extensions, but prefers public + addresses over temporary addresses. When false, the privacy extensions remain disabled. When + <literal>kernel</literal>, the kernel's default setting will be left in place. Defaults to + <literal>no</literal>.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>IPv6AcceptRA=</varname></term> + <listitem> + <para>Takes a boolean. Controls IPv6 Router Advertisement (RA) reception support for the + interface. If true, RAs are accepted; if false, RAs are ignored. When RAs are accepted, they + may trigger the start of the DHCPv6 client if the relevant flags are set in the RA data, or + if no routers are found on the link. The default is to disable RA reception for bridge + devices or when IP forwarding is enabled, and to enable it otherwise. Cannot be enabled on + bond devices and when link-local addressing is disabled.</para> + + <para>Further settings for the IPv6 RA support may be configured in the [IPv6AcceptRA] + section, see below.</para> + + <para>Also see + <ulink url="https://docs.kernel.org/networking/ip-sysctl.html">IP Sysctl</ulink> + in the kernel documentation regarding <literal>accept_ra</literal>, but note that systemd's + setting of <constant>1</constant> (i.e. true) corresponds to kernel's setting of + <constant>2</constant>.</para> + + <para>Note that kernel's implementation of the IPv6 RA protocol is always disabled, + regardless of this setting. If this option is enabled, a userspace implementation of the IPv6 + RA protocol is used, and the kernel's own implementation remains disabled, since + <command>systemd-networkd</command> needs to know all details supplied in the advertisements, + and these are not available from the kernel if the kernel's own implementation is used. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>IPv6DuplicateAddressDetection=</varname></term> + <listitem> + <para>Configures the amount of IPv6 Duplicate Address Detection (DAD) probes to send. When + unset, the kernel's default will be used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>IPv6HopLimit=</varname></term> + <listitem> + <para>Configures IPv6 Hop Limit. For each router that forwards the packet, the hop limit is + decremented by 1. When the hop limit field reaches zero, the packet is discarded. When unset, + the kernel's default will be used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>IPv4AcceptLocal=</varname></term> + <listitem> + <para>Takes a boolean. Accept packets with local source addresses. In combination with + suitable routing, this can be used to direct packets between two local interfaces over the + wire and have them accepted properly. When unset, the kernel's default will be used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>IPv4RouteLocalnet=</varname></term> + <listitem> + <para>Takes a boolean. When true, the kernel does not consider loopback addresses as martian + source or destination while routing. This enables the use of 127.0.0.0/8 for local routing + purposes. When unset, the kernel's default will be used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>IPv4ProxyARP=</varname></term> + <listitem> + <para>Takes a boolean. Configures proxy ARP for IPv4. Proxy ARP is the technique in which one + host, usually a router, answers ARP requests intended for another machine. By "faking" its + identity, the router accepts responsibility for routing packets to the "real" destination. + See <ulink url="https://tools.ietf.org/html/rfc1027">RFC 1027</ulink>. When unset, the + kernel's default will be used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>IPv6ProxyNDP=</varname></term> + <listitem> + <para>Takes a boolean. Configures proxy NDP for IPv6. Proxy NDP (Neighbor Discovery Protocol) + is a technique for IPv6 to allow routing of addresses to a different destination when peers + expect them to be present on a certain physical link. In this case a router answers Neighbour + Advertisement messages intended for another machine by offering its own MAC address as + destination. Unlike proxy ARP for IPv4, it is not enabled globally, but will only send + Neighbour Advertisement messages for addresses in the IPv6 neighbor proxy table, which can + also be shown by <command>ip -6 neighbour show proxy</command>. systemd-networkd will control + the per-interface `proxy_ndp` switch for each configured interface depending on this option. + When unset, the kernel's default will be used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>IPv6ProxyNDPAddress=</varname></term> + <listitem> + <para>An IPv6 address, for which Neighbour Advertisement messages will be proxied. This + option may be specified more than once. systemd-networkd will add the + <varname>IPv6ProxyNDPAddress=</varname> entries to the kernel's IPv6 neighbor proxy table. + This setting implies <varname>IPv6ProxyNDP=yes</varname> but has no effect if + <varname>IPv6ProxyNDP=</varname> has been set to false. When unset, the kernel's default will + be used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>IPv6SendRA=</varname></term> + <listitem> + <para>Whether to enable or disable Router Advertisement sending on a link. Takes a boolean + value. When enabled, prefixes configured in [IPv6Prefix] sections and routes configured in + the [IPv6RoutePrefix] sections are distributed as defined in the [IPv6SendRA] section. If + <varname>DHCPPrefixDelegation=</varname> is enabled, then the delegated prefixes are also + distributed. See <varname>DHCPPrefixDelegation=</varname> setting and the [IPv6SendRA], + [IPv6Prefix], [IPv6RoutePrefix], and [DHCPPrefixDelegation] sections for more configuration + options.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>DHCPPrefixDelegation=</varname></term> + <listitem> + <para>Takes a boolean value. When enabled, requests subnet prefixes on another link via the DHCPv6 + protocol or via the 6RD option in the DHCPv4 protocol. An address within each delegated prefix will + be assigned, and the prefixes will be announced through IPv6 Router Advertisement if + <varname>IPv6SendRA=</varname> is enabled. This behaviour can be configured in the + [DHCPPrefixDelegation] section. Defaults to disabled.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>IPv6MTUBytes=</varname></term> + <listitem> + <para>Configures IPv6 maximum transmission unit (MTU). An integer greater than or equal to + 1280 bytes. When unset, the kernel's default will be used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>KeepMaster=</varname></term> + <listitem> + <para>Takes a boolean value. When enabled, the current master interface index will not be + changed, and <varname>BatmanAdvanced=</varname>, <varname>Bond=</varname>, + <varname>Bridge=</varname>, and <varname>VRF=</varname> settings are ignored. This may be + useful when a netdev with a master interface is created by another program, e.g. + <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry>. + Defaults to false.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>BatmanAdvanced=</varname></term> + <term><varname>Bond=</varname></term> + <term><varname>Bridge=</varname></term> + <term><varname>VRF=</varname></term> + <listitem> + <para>The name of the B.A.T.M.A.N. Advanced, bond, bridge, or VRF interface to add the link + to. See + <citerefentry><refentrytitle>systemd.netdev</refentrytitle><manvolnum>5</manvolnum></citerefentry>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>IPoIB=</varname></term> + <term><varname>IPVLAN=</varname></term> + <term><varname>IPVTAP=</varname></term> + <term><varname>MACsec=</varname></term> + <term><varname>MACVLAN=</varname></term> + <term><varname>MACVTAP=</varname></term> + <term><varname>Tunnel=</varname></term> + <term><varname>VLAN=</varname></term> + <term><varname>VXLAN=</varname></term> + <term><varname>Xfrm=</varname></term> + <listitem> + <para>The name of an IPoIB, IPVLAN, IPVTAP, MACsec, MACVLAN, MACVTAP, tunnel, VLAN, + VXLAN, or Xfrm to be created on the link. See + <citerefentry><refentrytitle>systemd.netdev</refentrytitle><manvolnum>5</manvolnum></citerefentry>. + This option may be specified more than once.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>ActiveSlave=</varname></term> + <listitem> + <para>Takes a boolean. Specifies the new active slave. The <literal>ActiveSlave=</literal> + option is only valid for following modes: <literal>active-backup</literal>, + <literal>balance-alb</literal>, and <literal>balance-tlb</literal>. Defaults to false.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>PrimarySlave=</varname></term> + <listitem> + <para>Takes a boolean. Specifies which slave is the primary device. The specified device will + always be the active slave while it is available. Only when the primary is off-line will + alternate devices be used. This is useful when one slave is preferred over another, e.g. + when one slave has higher throughput than another. The <literal>PrimarySlave=</literal> + option is only valid for following modes: <literal>active-backup</literal>, + <literal>balance-alb</literal>, and <literal>balance-tlb</literal>. Defaults to false.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>ConfigureWithoutCarrier=</varname></term> + <listitem> + <para>Takes a boolean. Allows networkd to configure a specific link even if it has no + carrier. Defaults to false. If enabled, and the <varname>IgnoreCarrierLoss=</varname> setting + is not explicitly set, then it is enabled as well.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>IgnoreCarrierLoss=</varname></term> + <listitem> + <para>Takes a boolean or a timespan. When true, <command>systemd-networkd</command> retains + both the static and dynamic configuration of the interface even if its carrier is lost. When + false, <command>systemd-networkd</command> drops both the static and dynamic configuration of + the interface. When a timespan is specified, <command>systemd-networkd</command> waits for + the specified timespan, and ignores the carrier loss if the link regain its carrier within + the timespan. Setting 0 seconds is equivalent to <literal>no</literal>, and + <literal>infinite</literal> is equivalent to <literal>yes</literal>.</para> + + <para>Setting a finite timespan may be useful when e.g. in the following cases: + <itemizedlist> + <listitem> + <para>A wireless interface connecting to a network which has multiple access points with + the same SSID.</para> + </listitem> + <listitem> + <para>Enslaving a wireless interface to a bond interface, which may disconnect from the + connected access point and causes its carrier to be lost.</para> + </listitem> + <listitem> + <para>The driver of the interface resets when the MTU is changed.</para> + </listitem> + </itemizedlist> + </para> + + <para>When <varname>Bond=</varname> is specified to a wireless interface, defaults to 3 + seconds. When the DHCPv4 client is enabled and <varname>UseMTU=</varname> in the [DHCPv4] + section enabled, defaults to 5 seconds. Otherwise, defaults to the value specified with + <varname>ConfigureWithoutCarrier=</varname>. When <varname>ActivationPolicy=</varname> is set + to <literal>always-up</literal>, this is forced to <literal>yes</literal>, and ignored any + user specified values.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>KeepConfiguration=</varname></term> + <listitem> + <para>Takes a boolean or one of <literal>static</literal>, <literal>dhcp-on-stop</literal>, + <literal>dhcp</literal>. When <literal>static</literal>, <command>systemd-networkd</command> + will not drop static addresses and routes on starting up process. When set to + <literal>dhcp-on-stop</literal>, <command>systemd-networkd</command> will not drop addresses + and routes on stopping the daemon. When <literal>dhcp</literal>, + the addresses and routes provided by a DHCP server will never be dropped even if the DHCP + lease expires. This is contrary to the DHCP specification, but may be the best choice if, + e.g., the root filesystem relies on this connection. The setting <literal>dhcp</literal> + implies <literal>dhcp-on-stop</literal>, and <literal>yes</literal> implies + <literal>dhcp</literal> and <literal>static</literal>. Defaults to + <literal>dhcp-on-stop</literal> when <command>systemd-networkd</command> is running in + initrd, <literal>yes</literal> when the root filesystem is a network filesystem, and + <literal>no</literal> otherwise.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[Address] Section Options</title> + + <para>An [Address] section accepts the following keys. Specify several [Address] sections to + configure several addresses.</para> + + <variablelist class='network-directives'> + <varlistentry> + <term><varname>Address=</varname></term> + <listitem> + <para>As in the [Network] section. This setting is mandatory. Each [Address] section can + contain one <varname>Address=</varname> setting.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Peer=</varname></term> + <listitem> + <para>The peer address in a point-to-point connection. Accepts the same format as the + <varname>Address=</varname> setting.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Broadcast=</varname></term> + <listitem> + <para>Takes an IPv4 address or boolean value. The address must be in the format described in + <citerefentry project='man-pages'><refentrytitle>inet_pton</refentrytitle><manvolnum>3</manvolnum></citerefentry>. + If set to true, then the IPv4 broadcast address will be derived from the + <varname>Address=</varname> setting. If set to false, then the broadcast address will not be + set. Defaults to true, except for wireguard interfaces, where it default to false.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Label=</varname></term> + <listitem> + <para>Specifies the label for the IPv4 address. The label must be a 7-bit ASCII string with + a length of 1…15 characters. Defaults to unset.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>PreferredLifetime=</varname></term> + <listitem> + <para>Allows the default "preferred lifetime" of the address to be overridden. Only three + settings are accepted: <literal>forever</literal>, <literal>infinity</literal>, which is the + default and means that the address never expires, and <literal>0</literal>, which means that + the address is considered immediately "expired" and will not be used, unless explicitly + requested. A setting of <option>PreferredLifetime=0</option> is useful for addresses which + are added to be used only by a specific application, which is then configured to use them + explicitly.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Scope=</varname></term> + <listitem> + <para>The scope of the address, which can be <literal>global</literal> (valid everywhere on + the network, even through a gateway), <literal>link</literal> (only valid on this device, + will not traverse a gateway) or <literal>host</literal> (only valid within the device itself, + e.g. 127.0.0.1) or an integer in the range 0…255. Defaults to <literal>global</literal>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>RouteMetric=</varname></term> + <listitem> + <para>The metric of the prefix route, which is pointing to the subnet of the configured IP + address, taking the configured prefix length into account. Takes an unsigned integer in the + range 0…4294967295. When unset or set to 0, the kernel's default value is used. This + setting will be ignored when <varname>AddPrefixRoute=</varname> is false.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>HomeAddress=</varname></term> + <listitem> + <para>Takes a boolean. Designates this address the "home address" as defined in + <ulink url="https://tools.ietf.org/html/rfc6275">RFC 6275</ulink>. Supported only on IPv6. + Defaults to false.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>DuplicateAddressDetection=</varname></term> + <listitem> + <para>Takes one of <literal>ipv4</literal>, <literal>ipv6</literal>, <literal>both</literal>, + or <literal>none</literal>. When <literal>ipv4</literal>, performs IPv4 Address Conflict + Detection. See <ulink url="https://tools.ietf.org/html/rfc5227">RFC 5227</ulink>. + When <literal>ipv6</literal>, performs IPv6 Duplicate Address Detection. See + <ulink url="https://tools.ietf.org/html/rfc4862">RFC 4862</ulink>. Defaults to + <literal>ipv4</literal> for IPv4 link-local addresses, <literal>ipv6</literal> for IPv6 + addresses, and <literal>none</literal> otherwise.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>ManageTemporaryAddress=</varname></term> + <listitem> + <para>Takes a boolean. If true the kernel manage temporary addresses created from this one as + template on behalf of Privacy Extensions + <ulink url="https://tools.ietf.org/html/rfc3041">RFC 3041</ulink>. For this to become active, + the use_tempaddr sysctl setting has to be set to a value greater than zero. The given address + needs to have a prefix length of 64. This flag allows using privacy extensions in a manually + configured network, just like if stateless auto-configuration was active. Defaults to false. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>AddPrefixRoute=</varname></term> + <listitem> + <para>Takes a boolean. When true, the prefix route for the address is automatically added. + Defaults to true.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>AutoJoin=</varname></term> + <listitem> + <para>Takes a boolean. Joining multicast group on ethernet level via + <command>ip maddr</command> command would not work if we have an Ethernet switch that does + IGMP snooping since the switch would not replicate multicast packets on ports that did not + have IGMP reports for the multicast addresses. Linux vxlan interfaces created via + <command>ip link add vxlan</command> or networkd's netdev kind vxlan have the group option + that enables them to do the required join. By extending <command>ip address</command> command + with option <literal>autojoin</literal> we can get similar functionality for openvswitch (OVS) + vxlan interfaces as well as other tunneling mechanisms that need to receive multicast traffic. + Defaults to <literal>no</literal>.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>NetLabel=</varname><replaceable>label</replaceable></term> + <listitem> + + <para>This setting provides a method for integrating static and dynamic network configuration into + Linux <ulink url="https://docs.kernel.org/netlabel/index.html">NetLabel</ulink> subsystem rules, + used by <ulink url="https://en.wikipedia.org/wiki/Linux_Security_Modules">Linux Security Modules + (LSMs)</ulink> for network access control. The label, with suitable LSM rules, can be used to + control connectivity of (for example) a service with peers in the local network. At least with + SELinux, only the ingress can be controlled but not egress. The benefit of using this setting is + that it may be possible to apply interface independent part of NetLabel configuration at very early + stage of system boot sequence, at the time when the network interfaces are not available yet, with + <citerefentry + project='man-pages'><refentrytitle>netlabelctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>, + and the per-interface configuration with <command>systemd-networkd</command> once the interfaces + appear later. Currently this feature is only implemented for SELinux.</para> + + <para>The option expects a single NetLabel label. The label must conform to lexical restrictions of + LSM labels. When an interface is configured with IP addresses, the addresses and subnetwork masks + will be appended to the <ulink + url="https://github.com/SELinuxProject/selinux-notebook/blob/main/src/network_support.md">NetLabel + Fallback Peer Labeling</ulink> rules. They will be removed when the interface is + deconfigured. Failures to manage the labels will be ignored.</para> + + <para>Warning: Once labeling is enabled for network traffic, a lot of LSM access control points in + Linux networking stack go from dormant to active. Care should be taken to avoid getting into a + situation where for example remote connectivity is broken, when the security policy hasn't been + updated to consider LSM per-packet access controls and no rules would allow any network + traffic. Also note that additional configuration with <citerefentry + project='man-pages'><refentrytitle>netlabelctl</refentrytitle><manvolnum>8</manvolnum></citerefentry> + is needed.</para> + + <para>Example: + <programlisting>[Address] +NetLabel=system_u:object_r:localnet_peer_t:s0</programlisting> + + With the example rules applying for interface <literal>eth0</literal>, when the interface is + configured with an IPv4 address of 10.0.0.123/8, <command>systemd-networkd</command> performs the + equivalent of <command>netlabelctl</command> operation + + <programlisting>netlabelctl unlbl add interface eth0 address:10.0.0.0/8 label:system_u:object_r:localnet_peer_t:s0</programlisting> + + and the reverse operation when the IPv4 address is deconfigured. The configuration can be used with + LSM rules; in case of SELinux to allow a SELinux domain to receive data from objects of SELinux + <literal>peer</literal> class. For example: + + <programlisting>type localnet_peer_t; +allow my_server_t localnet_peer_t:peer recv;</programlisting> + + The effect of the above configuration and rules (in absence of other rules as may be the case) is + to only allow <literal>my_server_t</literal> (and nothing else) to receive data from local subnet + 10.0.0.0/8 of interface <literal>eth0</literal>. + </para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[Neighbor] Section Options</title> + + <para>A [Neighbor] section accepts the following keys. The neighbor section adds a permanent, + static entry to the neighbor table (IPv6) or ARP table (IPv4) for the given hardware address on the + links matched for the network. Specify several [Neighbor] sections to configure several static + neighbors.</para> + + <variablelist class='network-directives'> + <varlistentry> + <term><varname>Address=</varname></term> + <listitem> + <para>The IP address of the neighbor.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>LinkLayerAddress=</varname></term> + <listitem> + <para>The link layer address (MAC address or IP address) of the neighbor.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[IPv6AddressLabel] Section Options</title> + + <para>An [IPv6AddressLabel] section accepts the following keys. Specify several [IPv6AddressLabel] + sections to configure several address labels. IPv6 address labels are used for address selection. + See <ulink url="https://tools.ietf.org/html/rfc3484">RFC 3484</ulink>. Precedence is managed by + userspace, and only the label itself is stored in the kernel.</para> + + <variablelist class='network-directives'> + <varlistentry> + <term><varname>Label=</varname></term> + <listitem> + <para>The label for the prefix, an unsigned integer in the range 0…4294967294. 0xffffffff is + reserved. This setting is mandatory.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Prefix=</varname></term> + <listitem> + <para>IPv6 prefix is an address with a prefix length, separated by a slash + <literal>/</literal> character. This setting is mandatory. </para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[RoutingPolicyRule] Section Options</title> + + <para>An [RoutingPolicyRule] section accepts the following settings. Specify several + [RoutingPolicyRule] sections to configure several rules.</para> + + <variablelist class='network-directives'> + <varlistentry> + <term><varname>TypeOfService=</varname></term> + <listitem> + <para>Takes a number between 0 and 255 that specifies the type of service to match.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>From=</varname></term> + <listitem> + <para>Specifies the source address prefix to match. Possibly followed by a slash and the + prefix length.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>To=</varname></term> + <listitem> + <para>Specifies the destination address prefix to match. Possibly followed by a slash and the + prefix length.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>FirewallMark=</varname></term> + <listitem> + <para>Specifies the iptables firewall mark value to match (a number in the range + 1…4294967295). Optionally, the firewall mask (also a number between 1…4294967295) can be + suffixed with a slash (<literal>/</literal>), e.g., <literal>7/255</literal>.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Table=</varname></term> + <listitem> + <para>Specifies the routing table identifier to lookup if the rule selector matches. Takes + one of predefined names <literal>default</literal>, <literal>main</literal>, and + <literal>local</literal>, and names defined in <varname>RouteTable=</varname> in + <citerefentry><refentrytitle>networkd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + or a number between 1 and 4294967295. Defaults to <literal>main</literal>.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Priority=</varname></term> + <listitem> + <para>Specifies the priority of this rule. <varname>Priority=</varname> is an integer in the + range 0…4294967295. Higher number means lower priority, and rules get processed in order of + increasing number. Defaults to unset, and the kernel will pick a value dynamically.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>IncomingInterface=</varname></term> + <listitem> + <para>Specifies incoming device to match. If the interface is loopback, the rule only matches + packets originating from this host.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>OutgoingInterface=</varname></term> + <listitem> + <para>Specifies the outgoing device to match. The outgoing interface is only available for + packets originating from local sockets that are bound to a device.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>SourcePort=</varname></term> + <listitem> + <para>Specifies the source IP port or IP port range match in forwarding information base + (FIB) rules. A port range is specified by the lower and upper port separated by a dash. + Defaults to unset.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>DestinationPort=</varname></term> + <listitem> + <para>Specifies the destination IP port or IP port range match in forwarding information base + (FIB) rules. A port range is specified by the lower and upper port separated by a dash. + Defaults to unset.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>IPProtocol=</varname></term> + <listitem> + <para>Specifies the IP protocol to match in forwarding information base (FIB) rules. Takes IP + protocol name such as <literal>tcp</literal>, <literal>udp</literal> or + <literal>sctp</literal>, or IP protocol number such as <literal>6</literal> for + <literal>tcp</literal> or <literal>17</literal> for <literal>udp</literal>. Defaults to unset. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>InvertRule=</varname></term> + <listitem> + <para>A boolean. Specifies whether the rule is to be inverted. Defaults to false.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Family=</varname></term> + <listitem> + <para>Takes a special value <literal>ipv4</literal>, <literal>ipv6</literal>, or + <literal>both</literal>. By default, the address family is determined by the address + specified in <varname>To=</varname> or <varname>From=</varname>. If neither + <varname>To=</varname> nor <varname>From=</varname> are specified, then defaults to + <literal>ipv4</literal>.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>User=</varname></term> + <listitem> + <para>Takes a username, a user ID, or a range of user IDs separated by a dash. Defaults to + unset.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>SuppressPrefixLength=</varname></term> + <listitem> + <para>Takes a number <replaceable>N</replaceable> in the range 0…128 and rejects routing + decisions that have a prefix length of <replaceable>N</replaceable> or less. Defaults to + unset.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>SuppressInterfaceGroup=</varname></term> + <listitem> + <para>Takes an integer in the range 0…2147483647 and rejects routing decisions that have + an interface with the same group id. It has the same meaning as + <option>suppress_ifgroup</option> in <command>ip rule</command>. Defaults to unset.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Type=</varname></term> + <listitem> + <para>Specifies Routing Policy Database (RPDB) rule type. Takes one of + <literal>blackhole</literal>, <literal>unreachable</literal> or <literal>prohibit</literal>. + </para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[NextHop] Section Options</title> + + <para>The [NextHop] section is used to manipulate entries in the kernel's "nexthop" tables. The + [NextHop] section accepts the following settings. Specify several [NextHop] sections to configure + several hops.</para> + + <variablelist class='network-directives'> + <varlistentry> + <term><varname>Id=</varname></term> + <listitem> + <para>The id of the next hop. Takes an integer in the range 1…4294967295. If unspecified, + then automatically chosen by kernel.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Gateway=</varname></term> + <listitem> + <para>As in the [Network] section.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Family=</varname></term> + <listitem> + <para>Takes one of the special values <literal>ipv4</literal> or <literal>ipv6</literal>. + By default, the family is determined by the address specified in + <varname>Gateway=</varname>. If <varname>Gateway=</varname> is not specified, then defaults + to <literal>ipv4</literal>.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>OnLink=</varname></term> + <listitem> + <para>Takes a boolean. If set to true, the kernel does not have to check if the gateway is + reachable directly by the current machine (i.e., attached to the local network), so that we + can insert the nexthop in the kernel table without it being complained about. Defaults to + <literal>no</literal>.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Blackhole=</varname></term> + <listitem> + <para>Takes a boolean. If enabled, packets to the corresponding routes are discarded + silently, and <varname>Gateway=</varname> cannot be specified. Defaults to + <literal>no</literal>.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Group=</varname></term> + <listitem> + <para>Takes a whitespace separated list of nexthop IDs. Each ID must be in the range + 1…4294967295. Optionally, each nexthop ID can take a weight after a colon + (<literal><replaceable>id</replaceable><optional>:<replaceable>weight</replaceable></optional></literal>). + The weight must be in the range 1…255. If the weight is not specified, then it is assumed + that the weight is 1. This setting cannot be specified with <varname>Gateway=</varname>, + <varname>Family=</varname>, <varname>Blackhole=</varname>. This setting can be specified + multiple times. If an empty string is assigned, then the all previous assignments are + cleared. Defaults to unset.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[Route] Section Options</title> + + <para>The [Route] section accepts the following settings. Specify several [Route] sections to + configure several routes.</para> + + <variablelist class='network-directives'> + <varlistentry> + <term><varname>Gateway=</varname></term> + <listitem> + <para>Takes the gateway address or the special values <literal>_dhcp4</literal> and + <literal>_ipv6ra</literal>. If <literal>_dhcp4</literal> or <literal>_ipv6ra</literal> is + set, then the gateway address provided by DHCPv4 or IPv6 RA is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>GatewayOnLink=</varname></term> + <listitem> + <para>Takes a boolean. If set to true, the kernel does not have to check if the gateway is + reachable directly by the current machine (i.e., attached to the local network), so that we + can insert the route in the kernel table without it being complained about. Defaults to + <literal>no</literal>.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Destination=</varname></term> + <listitem> + <para>The destination prefix of the route. Possibly followed by a slash and the prefix + length. If omitted, a full-length host route is assumed.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Source=</varname></term> + <listitem> + <para>The source prefix of the route. Possibly followed by a slash and the prefix length. If + omitted, a full-length host route is assumed.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Metric=</varname></term> + <listitem> + <para>The metric of the route. Takes an unsigned integer in the range 0…4294967295. Defaults + to unset, and the kernel's default will be used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>IPv6Preference=</varname></term> + <listitem> + <para>Specifies the route preference as defined in + <ulink url="https://tools.ietf.org/html/rfc4191">RFC 4191</ulink> for Router Discovery + messages. Which can be one of <literal>low</literal> the route has a lowest priority, + <literal>medium</literal> the route has a default priority or <literal>high</literal> the + route has a highest priority.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Scope=</varname></term> + <listitem> + <para>The scope of the IPv4 route, which can be <literal>global</literal>, + <literal>site</literal>, <literal>link</literal>, <literal>host</literal>, or + <literal>nowhere</literal>:</para> + <itemizedlist> + <listitem> + <para><literal>global</literal> means the route can reach hosts more than one hop away. + </para> + </listitem> + + <listitem> + <para><literal>site</literal> means an interior route in the local autonomous system. + </para> + </listitem> + + <listitem> + <para><literal>link</literal> means the route can only reach hosts on the local network + (one hop away).</para> + </listitem> + + <listitem> + <para><literal>host</literal> means the route will not leave the local machine (used for + internal addresses like 127.0.0.1).</para> + </listitem> + + <listitem> + <para><literal>nowhere</literal> means the destination doesn't exist.</para> + </listitem> + </itemizedlist> + + <para>For IPv4 route, defaults to <literal>host</literal> if <varname>Type=</varname> is + <literal>local</literal> or <literal>nat</literal>, and <literal>link</literal> if + <varname>Type=</varname> is <literal>broadcast</literal>, <literal>multicast</literal>, + <literal>anycast</literal>, or <literal>unicast</literal>. In other cases, + defaults to <literal>global</literal>. The value is not used for IPv6.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>PreferredSource=</varname></term> + <listitem> + <para>The preferred source address of the route. The address must be in the format described + in + <citerefentry project='man-pages'><refentrytitle>inet_pton</refentrytitle><manvolnum>3</manvolnum></citerefentry>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Table=</varname></term> + <listitem> + <para>The table identifier for the route. Takes one of predefined names + <literal>default</literal>, <literal>main</literal>, and <literal>local</literal>, and names + defined in <varname>RouteTable=</varname> in + <citerefentry><refentrytitle>networkd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + or a number between 1 and 4294967295. The table can be retrieved using + <command>ip route show table <replaceable>num</replaceable></command>. If unset and + <varname>Type=</varname> is <literal>local</literal>, <literal>broadcast</literal>, + <literal>anycast</literal>, or <literal>nat</literal>, then <literal>local</literal> is used. + In other cases, defaults to <literal>main</literal>.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Protocol=</varname></term> + <listitem> + <para>The protocol identifier for the route. Takes a number between 0 and 255 or the special + values <literal>kernel</literal>, <literal>boot</literal>, <literal>static</literal>, + <literal>ra</literal> and <literal>dhcp</literal>. Defaults to <literal>static</literal>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Type=</varname></term> + <listitem> + <para>Specifies the type for the route. Takes one of <literal>unicast</literal>, + <literal>local</literal>, <literal>broadcast</literal>, <literal>anycast</literal>, + <literal>multicast</literal>, <literal>blackhole</literal>, <literal>unreachable</literal>, + <literal>prohibit</literal>, <literal>throw</literal>, <literal>nat</literal>, and + <literal>xresolve</literal>. If <literal>unicast</literal>, a regular route is defined, i.e. + a route indicating the path to take to a destination network address. If + <literal>blackhole</literal>, packets to the defined route are discarded silently. If + <literal>unreachable</literal>, packets to the defined route are discarded and the ICMP + message "Host Unreachable" is generated. If <literal>prohibit</literal>, packets to the + defined route are discarded and the ICMP message "Communication Administratively Prohibited" + is generated. If <literal>throw</literal>, route lookup in the current routing table will + fail and the route selection process will return to Routing Policy Database (RPDB). Defaults + to <literal>unicast</literal>.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>InitialCongestionWindow=</varname></term> + <listitem> + <para>The TCP initial congestion window is used during the start of a TCP connection. + During the start of a TCP session, when a client requests a resource, the server's initial + congestion window determines how many packets will be sent during the initial burst of data + without waiting for acknowledgement. Takes a number between 1 and 1023. Note that 100 is + considered an extremely large value for this option. When unset, the kernel's default + (typically 10) will be used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>InitialAdvertisedReceiveWindow=</varname></term> + <listitem> + <para>The TCP initial advertised receive window is the amount of receive data (in bytes) + that can initially be buffered at one time on a connection. The sending host can send only + that amount of data before waiting for an acknowledgment and window update from the + receiving host. Takes a number between 1 and 1023. Note that 100 is considered an extremely + large value for this option. When unset, the kernel's default will be used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>QuickAck=</varname></term> + <listitem> + <para>Takes a boolean. When true enables TCP quick ack mode for the route. When unset, the + kernel's default will be used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>FastOpenNoCookie=</varname></term> + <listitem> + <para>Takes a boolean. When true enables TCP fastopen without a cookie on a per-route basis. + When unset, the kernel's default will be used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>TTLPropagate=</varname></term> + <listitem> + <para>Takes a boolean. When true enables TTL propagation at Label Switched Path (LSP) egress. + When unset, the kernel's default will be used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>MTUBytes=</varname></term> + <listitem> + <para>The maximum transmission unit in bytes to set for the route. The usual suffixes K, M, + G, are supported and are understood to the base of 1024.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>TCPAdvertisedMaximumSegmentSize=</varname></term> + <listitem> + <para>Specifies the Path MSS (in bytes) hints given on TCP layer. The usual suffixes K, M, G, + are supported and are understood to the base of 1024. An unsigned integer in the range + 1…4294967294. When unset, the kernel's default will be used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>TCPCongestionControlAlgorithm=</varname></term> + <listitem> + <para>Specifies the TCP congestion control algorithm for the route. Takes a name of the algorithm, + e.g. <literal>bbr</literal>, <literal>dctcp</literal>, or <literal>vegas</literal>. When unset, + the kernel's default will be used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>MultiPathRoute=<replaceable>address</replaceable>[@<replaceable>name</replaceable>] [<replaceable>weight</replaceable>]</varname></term> + <listitem> + <para>Configures multipath route. Multipath routing is the technique of using multiple + alternative paths through a network. Takes gateway address. Optionally, takes a network + interface name or index separated with <literal>@</literal>, and a weight in 1..256 for this + multipath route separated with whitespace. This setting can be specified multiple times. If + an empty string is assigned, then the all previous assignments are cleared.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>NextHop=</varname></term> + <listitem> + <para>Specifies the nexthop id. Takes an unsigned integer in the range 1…4294967295. If set, + the corresponding [NextHop] section must be configured. Defaults to unset.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[DHCPv4] Section Options</title> + + <para>The [DHCPv4] section configures the DHCPv4 client, if it is enabled with the + <varname>DHCP=</varname> setting described above:</para> + + <variablelist class='network-directives'> + + <!-- DHCP packet contents --> + + <varlistentry> + <term><varname>SendHostname=</varname></term> + <listitem> + <para>When true (the default), the machine's hostname (or the value specified with + <varname>Hostname=</varname>, described below) will be sent to the DHCP server. Note that the + hostname must consist only of 7-bit ASCII lower-case characters and no spaces or dots, and be + formatted as a valid DNS domain name. Otherwise, the hostname is not sent even if this option + is true.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Hostname=</varname></term> + <listitem> + <para>Use this value for the hostname which is sent to the DHCP server, instead of machine's + hostname. Note that the specified hostname must consist only of 7-bit ASCII lower-case + characters and no spaces or dots, and be formatted as a valid DNS domain name.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>MUDURL=</varname></term> + <listitem> + <para>When configured, the specified Manufacturer Usage Description (MUD) URL will be sent + to the DHCPv4 server. Takes a URL of length up to 255 characters. A superficial verification + that the string is a valid URL will be performed. DHCPv4 clients are intended to have at most + one MUD URL associated with them. See + <ulink url="https://tools.ietf.org/html/rfc8520">RFC 8520</ulink>.</para> + + <para>MUD is an embedded software standard defined by the IETF that allows IoT device makers + to advertise device specifications, including the intended communication patterns for their + device when it connects to the network. The network can then use this to author a + context-specific access policy, so the device functions only within those parameters.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>ClientIdentifier=</varname></term> + <listitem> + <para>The DHCPv4 client identifier to use. Takes one of <option>mac</option>, + <option>duid</option> or <option>duid-only</option>. If set to <option>mac</option>, the + MAC address of the link is used. If set to <option>duid</option>, an RFC4361-compliant Client + ID, which is the combination of IAID and DUID (see below), is used. If set to + <option>duid-only</option>, only DUID is used, this may not be RFC compliant, but some setups + may require to use this. Defaults to <option>duid</option>.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>VendorClassIdentifier=</varname></term> + <listitem> + <para>The vendor class identifier used to identify vendor type and configuration.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>UserClass=</varname></term> + <listitem> + <para>A DHCPv4 client can use UserClass option to identify the type or category of user or + applications it represents. The information contained in this option is a string that + represents the user class of which the client is a member. Each class sets an identifying + string of information to be used by the DHCP service to classify clients. Takes a + whitespace-separated list of strings.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>DUIDType=</varname></term> + <listitem> + <para>Override the global <varname>DUIDType=</varname> setting for this network. See + <citerefentry><refentrytitle>networkd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> + for a description of possible values.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>DUIDRawData=</varname></term> + <listitem> + <para>Override the global <varname>DUIDRawData=</varname> setting for this network. See + <citerefentry><refentrytitle>networkd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> + for a description of possible values.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>IAID=</varname></term> + <listitem> + <para>The DHCP Identity Association Identifier (IAID) for the interface, a 32-bit unsigned + integer.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Anonymize=</varname></term> + <listitem> + <para>Takes a boolean. When true, the options sent to the DHCP server will follow the + <ulink url="https://tools.ietf.org/html/rfc7844">RFC 7844</ulink> (Anonymity Profiles for + DHCP Clients) to minimize disclosure of identifying information. Defaults to false.</para> + + <para>This option should only be set to true when <varname>MACAddressPolicy=</varname> is set + to <option>random</option> (see + <citerefentry><refentrytitle>systemd.link</refentrytitle><manvolnum>5</manvolnum></citerefentry>). + </para> + + <para>When true, + <varname>ClientIdentifier=mac</varname>, + <varname>SendHostname=no</varname>, + <varname>Use6RD=no</varname>, + <varname>UseCaptivePortal=no</varname>, + <varname>UseMTU=no</varname>, + <varname>UseNTP=no</varname>, + <varname>UseSIP=no</varname>, and + <varname>UseTimezone=no</varname> + are implied and these settings in the .network file are silently ignored. Also, + <varname>Hostname=</varname>, + <varname>MUDURL=</varname>, + <varname>RequestOptions=</varname>, + <varname>SendOption=</varname>, + <varname>SendVendorOption=</varname>, + <varname>UserClass=</varname>, and + <varname>VendorClassIdentifier=</varname> + are silently ignored.</para> + + <para>With this option enabled DHCP requests will mimic those generated by Microsoft + Windows, in order to reduce the ability to fingerprint and recognize installations. This + means DHCP request sizes will grow and lease data will be more comprehensive than normally, + though most of the requested data is not actually used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>RequestOptions=</varname></term> + <listitem> + <para>Sets request options to be sent to the server in the DHCPv4 request options list. A + whitespace-separated list of integers in the range 1…254. Defaults to unset.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>SendOption=</varname></term> + <listitem> + <para>Send an arbitrary raw option in the DHCPv4 request. Takes a DHCP option number, data + type and data separated with a colon + (<literal><replaceable>option</replaceable>:<replaceable>type</replaceable>:<replaceable>value</replaceable></literal>). + The option number must be an integer in the range 1…254. The type takes one of + <literal>uint8</literal>, <literal>uint16</literal>, <literal>uint32</literal>, + <literal>ipv4address</literal>, or <literal>string</literal>. Special characters in the data + string may be escaped using + <ulink url="https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style + escapes</ulink>. This setting can be specified multiple times. If an empty string is + specified, then all options specified earlier are cleared. Defaults to unset.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>SendVendorOption=</varname></term> + <listitem> + <para>Send an arbitrary vendor option in the DHCPv4 request. Takes a DHCP option number, data + type and data separated with a colon + (<literal><replaceable>option</replaceable>:<replaceable>type</replaceable>:<replaceable>value</replaceable></literal>). + The option number must be an integer in the range 1…254. The type takes one of + <literal>uint8</literal>, <literal>uint16</literal>, <literal>uint32</literal>, + <literal>ipv4address</literal>, or <literal>string</literal>. Special characters in the data + string may be escaped using + <ulink url="https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style + escapes</ulink>. This setting can be specified multiple times. If an empty string is specified, + then all options specified earlier are cleared. Defaults to unset.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>IPServiceType=</varname></term> + <listitem> + <para>Takes one of the special values <literal>none</literal>, <literal>CS6</literal>, or + <literal>CS4</literal>. When <literal>none</literal> no IP service type is set to the packet + sent from the DHCPv4 client. When <literal>CS6</literal> (network control) or + <literal>CS4</literal> (realtime), the corresponding service type will be set. Defaults to + <literal>CS6</literal>.</para> + </listitem> + </varlistentry> + + <!-- How to use the DHCP lease --> + + <varlistentry> + <term><varname>Label=</varname></term> + <listitem> + <para>Specifies the label for the IPv4 address received from the DHCP server. The label must + be a 7-bit ASCII string with a length of 1…15 characters. Defaults to unset.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>UseDNS=</varname></term> + <listitem> + <para>When true (the default), the DNS servers received from the DHCP server will be used. + </para> + + <para>This corresponds to the <option>nameserver</option> option in + <citerefentry project='man-pages'><refentrytitle>resolv.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>RoutesToDNS=</varname></term> + <listitem> + <para>When true, the routes to the DNS servers received from the DHCP server will be + configured. When <varname>UseDNS=</varname> is disabled, this setting is ignored. Defaults to + true.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>UseNTP=</varname></term> + <listitem> + <para>When true (the default), the NTP servers received from the DHCP server will be used by + <filename>systemd-timesyncd.service</filename>.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>RoutesToNTP=</varname></term> + <listitem> + <para>When true, the routes to the NTP servers received from the DHCP server will be + configured. When <varname>UseNTP=</varname> is disabled, this setting is ignored. Defaults to + true.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>UseSIP=</varname></term> + <listitem> + <para>When true (the default), the SIP servers received from the DHCP server will be collected + and made available to client programs.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>UseMTU=</varname></term> + <listitem> + <para>When true, the interface maximum transmission unit from the DHCP server will be used on + the current link. If <varname>MTUBytes=</varname> is set, then this setting is ignored. + Defaults to false.</para> + + <para>Note, some drivers will reset the interfaces if the MTU is changed. For such + interfaces, please try to use <varname>IgnoreCarrierLoss=</varname> with a short timespan, + e.g. <literal>3 seconds</literal>.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>UseHostname=</varname></term> + <listitem> + <para>When true (the default), the hostname received from the DHCP server will be set as the + transient hostname of the system.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>UseDomains=</varname></term> + <listitem> + <para>Takes a boolean, or the special value <option>route</option>. When true, the domain name + received from the DHCP server will be used as DNS search domain over this link, similarly to the + effect of the <option>Domains=</option> setting. If set to <option>route</option>, the domain name + received from the DHCP server will be used for routing DNS queries only, but not for searching, + similarly to the effect of the <option>Domains=</option> setting when the argument is prefixed with + <literal>~</literal>. Defaults to false.</para> + + <para>It is recommended to enable this option only on trusted networks, as setting this + affects resolution of all hostnames, in particular of single-label names. It is generally + safer to use the supplied domain only as routing domain, rather than as search domain, in + order to not have it affect local resolution of single-label names.</para> + + <para>When set to true, this setting corresponds to the <option>domain</option> option in + <citerefentry project='man-pages'><refentrytitle>resolv.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>UseRoutes=</varname></term> + <listitem> + <para>When true (the default), the static routes will be requested from the DHCP server and + added to the routing table with a metric of 1024, and a scope of <option>global</option>, + <option>link</option> or <option>host</option>, depending on the route's destination and + gateway. If the destination is on the local host, e.g., 127.x.x.x, or the same as the link's + own address, the scope will be set to <option>host</option>. Otherwise if the gateway is null + (a direct route), a <option>link</option> scope will be used. For anything else, scope + defaults to <option>global</option>.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>RouteMetric=</varname></term> + <listitem> + <para>Set the routing metric for routes specified by the DHCP server (including the prefix + route added for the specified prefix). Takes an unsigned integer in the range 0…4294967295. + Defaults to 1024.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>RouteTable=<replaceable>num</replaceable></varname></term> + <listitem> + <para>The table identifier for DHCP routes. Takes one of predefined names + <literal>default</literal>, <literal>main</literal>, and <literal>local</literal>, and names + defined in <varname>RouteTable=</varname> in + <citerefentry><refentrytitle>networkd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + or a number between 1…4294967295.</para> + + <para>When used in combination with <varname>VRF=</varname>, the VRF's routing table is + used when this parameter is not specified.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>RouteMTUBytes=</varname></term> + <listitem> + <para>Specifies the MTU for the DHCP routes. Please see the [Route] section for further + details.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>UseGateway=</varname></term> + <listitem> + <para>When true, the gateway will be requested from the DHCP server and added to the routing + table with a metric of 1024, and a scope of <option>link</option>. When unset, the value + specified with <varname>UseRoutes=</varname> is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>UseTimezone=</varname></term> + <listitem><para>When true, the timezone received from the DHCP server will be set as timezone + of the local system. Defaults to false.</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>Use6RD=</varname></term> + <listitem> + <para>When true, subnets of the received IPv6 prefix are assigned to downstream interfaces + which enables <varname>DHCPPrefixDelegation=</varname>. See also + <varname>DHCPPrefixDelegation=</varname> in the [Network] section, the [DHCPPrefixDelegation] + section, and <ulink url="https://tools.ietf.org/html/rfc5969">RFC 5969</ulink>. Defaults to + false.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>FallbackLeaseLifetimeSec=</varname></term> + <listitem> + <para>Allows one to set DHCPv4 lease lifetime when DHCPv4 server does not send the lease + lifetime. Takes one of <literal>forever</literal> or <literal>infinity</literal>. If + specified, the acquired address never expires. Defaults to unset.</para> + </listitem> + </varlistentry> + + <!-- How to communicate with the server --> + + <varlistentry> + <term><varname>RequestBroadcast=</varname></term> + <listitem> + <para>Request the server to use broadcast messages before the IP address has been configured. + This is necessary for devices that cannot receive RAW packets, or that cannot receive packets + at all before an IP address has been configured. On the other hand, this must not be enabled + on networks where broadcasts are filtered out.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>MaxAttempts=</varname></term> + <listitem> + <para>Specifies how many times the DHCPv4 client configuration should be attempted. Takes a + number or <literal>infinity</literal>. Defaults to <literal>infinity</literal>. Note that the + time between retries is increased exponentially, up to approximately one per minute, so the + network will not be overloaded even if this number is high. The default is suitable in most + circumstances.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>ListenPort=</varname></term> + <listitem> + <para>Set the port from which the DHCP client packets originate.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>DenyList=</varname></term> + <listitem> + <para>A whitespace-separated list of IPv4 addresses. Each address can optionally take a + prefix length after <literal>/</literal>. DHCP offers from servers in the list are rejected. + Note that if <varname>AllowList=</varname> is configured then <varname>DenyList=</varname> is + ignored.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>AllowList=</varname></term> + <listitem> + <para>A whitespace-separated list of IPv4 addresses. Each address can optionally take a + prefix length after <literal>/</literal>. DHCP offers from servers in the list are accepted. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>SendRelease=</varname></term> + <listitem> + <para>When true, the DHCPv4 client sends a DHCP release packet when it stops. Defaults to + true.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>SendDecline=</varname></term> + <listitem> + <para>A boolean. When true, <command>systemd-networkd</command> performs IPv4 Duplicate + Address Detection to the acquired address by the DHCPv4 client. If duplicate is detected, + the DHCPv4 client rejects the address by sending a <constant>DHCPDECLINE</constant> packet to + the DHCP server, and tries to obtain an IP address again. See + <ulink url="https://tools.ietf.org/html/rfc5227">RFC 5227</ulink>. Defaults to false.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>NetLabel=</varname></term> + <listitem> + <para>This applies the NetLabel for the addresses received with DHCP, like + <varname>NetLabel=</varname> in [Address] section applies it to statically configured + addresses. See <varname>NetLabel=</varname> in [Address] section for more details.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[DHCPv6] Section Options</title> + + <para>The [DHCPv6] section configures the DHCPv6 client, if it is enabled with the + <varname>DHCP=</varname> setting described above, or invoked by the IPv6 Router Advertisement: + </para> + + <variablelist class='network-directives'> + + <!-- DHCP packet contents --> + + <varlistentry> + <term><varname>MUDURL=</varname></term> + <term><varname>IAID=</varname></term> + <term><varname>DUIDType=</varname></term> + <term><varname>DUIDRawData=</varname></term> + <term><varname>RequestOptions=</varname></term> + <listitem> + <para>As in the [DHCPv4] section.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>SendOption=</varname></term> + <listitem> + <para>As in the [DHCPv4] section, however because DHCPv6 uses 16-bit fields to store option + numbers, the option number is an integer in the range 1…65536.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>SendVendorOption=</varname></term> + <listitem> + <para>Send an arbitrary vendor option in the DHCPv6 request. Takes an enterprise identifier, + DHCP option number, data type, and data separated with a colon + (<literal><replaceable>enterprise identifier</replaceable>:<replaceable>option</replaceable>:<replaceable>type</replaceable>:<replaceable>value</replaceable></literal>). + Enterprise identifier is an unsigned integer in the range 1…4294967294. The option number + must be an integer in the range 1…254. Data type takes one of <literal>uint8</literal>, + <literal>uint16</literal>, <literal>uint32</literal>, <literal>ipv4address</literal>, + <literal>ipv6address</literal>, or <literal>string</literal>. Special characters in the data + string may be escaped using + <ulink url="https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style + escapes</ulink>. This setting can be specified multiple times. If an empty string is + specified, then all options specified earlier are cleared. Defaults to unset.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>UserClass=</varname></term> + <listitem> + <para>A DHCPv6 client can use User Class option to identify the type or category of user or + applications it represents. The information contained in this option is a string that + represents the user class of which the client is a member. Each class sets an identifying + string of information to be used by the DHCP service to classify clients. Special characters + in the data string may be escaped using + <ulink url="https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style + escapes</ulink>. This setting can be specified multiple times. If an empty string is + specified, then all options specified earlier are cleared. Takes a whitespace-separated list + of strings. Note that currently <constant>NUL</constant> bytes are not allowed.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>VendorClass=</varname></term> + <listitem> + <para>A DHCPv6 client can use VendorClass option to identify the vendor that manufactured the + hardware on which the client is running. The information contained in the data area of this + option is contained in one or more opaque fields that identify details of the hardware + configuration. Takes a whitespace-separated list of strings.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>PrefixDelegationHint=</varname></term> + <listitem> + <para>Takes an IPv6 address with prefix length in the same format as the + <varname>Address=</varname> in the [Network] section. The DHCPv6 client will include a prefix + hint in the DHCPv6 solicitation sent to the server. The prefix length must be in the range + 1…128. Defaults to unset.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>RapidCommit=</varname></term> + <listitem> + <para>Takes a boolean. The DHCPv6 client can obtain configuration parameters from a DHCPv6 server + through a rapid two-message exchange (solicit and reply). When the rapid commit option is set by + both the DHCPv6 client and the DHCPv6 server, the two-message exchange is used. Otherwise, the + four-message exchange (solicit, advertise, request, and reply) is used. The two-message exchange + provides faster client configuration. See + <ulink url="https://tools.ietf.org/html/rfc3315#section-17.2.1">RFC 3315</ulink> for details. + Defaults to true, and the two-message exchange will be used if the server support it.</para> + </listitem> + </varlistentry> + + <!-- How to use the DHCP lease --> + + <varlistentry> + <term><varname>UseAddress=</varname></term> + <listitem> + <para>When true (the default), the IP addresses provided by the DHCPv6 server will be + assigned.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>UseDelegatedPrefix=</varname></term> + <listitem> + <para>When true (the default), the client will request the DHCPv6 server to delegate + prefixes. If the server provides prefixes to be delegated, then subnets of the prefixes are + assigned to the interfaces that have <varname>DHCPPrefixDelegation=yes</varname>. + See also the <varname>DHCPPrefixDelegation=</varname> setting in the [Network] section, + settings in the [DHCPPrefixDelegation] section, and + <ulink url="https://www.rfc-editor.org/rfc/rfc8415.html#section-6.3">RFC 8415</ulink>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>UseDNS=</varname></term> + <term><varname>UseNTP=</varname></term> + <term><varname>UseHostname=</varname></term> + <term><varname>UseDomains=</varname></term> + <term><varname>NetLabel=</varname></term> + <listitem> + <para>As in the [DHCPv4] section.</para> + </listitem> + </varlistentry> + + <!-- How to communicate with the server --> + + <varlistentry> + <term><varname>WithoutRA=</varname></term> + <listitem> + <para>Allows DHCPv6 client to start without router advertisements's + <literal>managed</literal> or <literal>other configuration</literal> flag. Takes one of + <literal>no</literal>, <literal>solicit</literal>, or + <literal>information-request</literal>. If this is not specified, + <literal>solicit</literal> is used when <varname>DHCPPrefixDelegation=</varname> is enabled + and <varname>UplinkInterface=:self</varname> is specified in the [DHCPPrefixDelegation] + section. Otherwise, defaults to <literal>no</literal>, and the DHCPv6 client will be started + when an RA is received. See also the <varname>DHCPv6Client=</varname> setting in the + [IPv6AcceptRA] section.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[DHCPPrefixDelegation] Section Options</title> + <para>The [DHCPPrefixDelegation] section configures subnet prefixes of the delegated prefixes + acquired by a DHCPv6 client, or by a DHCPv4 client through the 6RD option on another interface. + The settings in this section are used only when the <varname>DHCPPrefixDelegation=</varname> + setting in the [Network] section is enabled.</para> + + <variablelist class='network-directives'> + <varlistentry> + <term><varname>UplinkInterface=</varname></term> + <listitem> + <para>Specifies the name or the index of the uplink interface, or one of the special values + <literal>:self</literal> and <literal>:auto</literal>. When <literal>:self</literal>, the + interface itself is considered the uplink interface, and + <varname>WithoutRA=solicit</varname> is implied if the setting is not explicitly specified. + When <literal>:auto</literal>, the first link which acquired prefixes to be delegated from + the DHCPv6 or DHCPv4 server is selected. Defaults to <literal>:auto</literal>.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>SubnetId=</varname></term> + <listitem> + <para>Configure a specific subnet ID on the interface from a (previously) received prefix + delegation. You can either set "auto" (the default) or a specific subnet ID (as defined in + <ulink url="https://tools.ietf.org/html/rfc4291#section-2.5.4">RFC 4291</ulink>, section + 2.5.4), in which case the allowed value is hexadecimal, from 0 to 0x7fffffffffffffff + inclusive.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Announce=</varname></term> + <listitem> + <para>Takes a boolean. When enabled, and <varname>IPv6SendRA=</varname> in [Network] section + is enabled, the delegated prefixes are distributed through the IPv6 Router Advertisement. + This setting will be ignored when the <varname>DHCPPrefixDelegation=</varname> setting is + enabled on the upstream interface. Defaults to yes.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Assign=</varname></term> + <listitem> + <para>Takes a boolean. Specifies whether to add an address from the delegated prefixes which + are received from the WAN interface by the DHCPv6 Prefix Delegation. When true (on LAN + interfce), the EUI-64 algorithm will be used by default to form an interface identifier from + the delegated prefixes. See also <varname>Token=</varname> setting below. Defaults to yes. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Token=</varname></term> + <listitem> + <para>Specifies an optional address generation mode for assigning an address in each + delegated prefix. This accepts the same syntax as <varname>Token=</varname> in the + [IPv6AcceptRA] section. If <varname>Assign=</varname> is set to false, then this setting will + be ignored. Defaults to unset, which means the EUI-64 algorithm will be used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>ManageTemporaryAddress=</varname></term> + <listitem> + <para>As in the [Address] section, but defaults to true.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>RouteMetric=</varname></term> + <listitem> + <para>The metric of the route to the delegated prefix subnet. Takes an unsigned integer in + the range 0…4294967295. When set to 0, the kernel's default value is used. Defaults to 256. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>NetLabel=</varname></term> + <listitem> + <para>This applies the NetLabel for the addresses received with DHCP, like + <varname>NetLabel=</varname> in [Address] section applies it to statically configured + addresses. See <varname>NetLabel=</varname> in [Address] section for more details.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[IPv6AcceptRA] Section Options</title> + <para>The [IPv6AcceptRA] section configures the IPv6 Router Advertisement (RA) client, if it is enabled + with the <varname>IPv6AcceptRA=</varname> setting described above:</para> + + <variablelist class='network-directives'> + <varlistentry> + <term><varname>Token=</varname></term> + <listitem> + <para>Specifies an optional address generation mode for the Stateless Address + Autoconfiguration (SLAAC). The following values are supported:</para> + + <variablelist> + <varlistentry> + <term><option>eui64</option></term> + <listitem> + <para> + The EUI-64 algorithm will be used to generate an address for that prefix. Only + supported by Ethernet or InfiniBand interfaces. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term><option>static:<replaceable>ADDRESS</replaceable></option></term> + <listitem> + <para> + An IPv6 address must be specified after a colon (<literal>:</literal>), and the + lower bits of the supplied address are combined with the upper bits of a prefix + received in a Router Advertisement (RA) message to form a complete address. Note + that if multiple prefixes are received in an RA message, or in multiple RA messages, + addresses will be formed from each of them using the supplied address. This mode + implements SLAAC but uses a static interface identifier instead of an identifier + generated by using the EUI-64 algorithm. Because the interface identifier is static, + if Duplicate Address Detection detects that the computed address is a duplicate + (in use by another node on the link), then this mode will fail to provide an address + for that prefix. If an IPv6 address without mode is specified, then + <literal>static</literal> mode is assumed. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term><option>prefixstable[:<replaceable>ADDRESS</replaceable>][,<replaceable>UUID</replaceable>]</option></term> + <listitem> + <para> + The algorithm specified in + <ulink url="https://tools.ietf.org/html/rfc7217">RFC 7217</ulink> will be used to + generate interface identifiers. This mode can optionally take an IPv6 address + separated with a colon (<literal>:</literal>). If an IPv6 address is specified, + then an interface identifier is generated only when a prefix received in an RA + message matches the supplied address. + </para> + <para> + This mode can also optionally take a non-null UUID in the format which + <function>sd_id128_from_string()</function> accepts, e.g. + <literal>86b123b969ba4b7eb8b3d8605123525a</literal> or + <literal>86b123b9-69ba-4b7e-b8b3-d8605123525a</literal>. If a UUID is specified, the + value is used as the secret key to generate interface identifiers. If not specified, + then an application specific ID generated with the system's machine-ID will be used + as the secret key. See + <citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_id128_from_string</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + and + <citerefentry><refentrytitle>sd_id128_get_machine</refentrytitle><manvolnum>3</manvolnum></citerefentry>. + </para> + <para> + Note that the <literal>prefixstable</literal> algorithm uses both the interface + name and MAC address as input to the hash to compute the interface identifier, so + if either of those are changed the resulting interface identifier (and address) + will be changed, even if the prefix received in the RA message has not been + changed. + </para> + </listitem> + </varlistentry> + </variablelist> + + <para>If no address generation mode is specified (which is the default), or a received + prefix does not match any of the addresses provided in <literal>prefixstable</literal> + mode, then the EUI-64 algorithm will be used for Ethernet or InfiniBand interfaces, + otherwise <literal>prefixstable</literal> will be used to form an interface identifier for + that prefix.</para> + + <para>This setting can be specified multiple times. If an empty string is assigned, then + the all previous assignments are cleared.</para> + + <para>Examples: + <programlisting>Token=eui64 +Token=::1a:2b:3c:4d +Token=static:::1a:2b:3c:4d +Token=prefixstable +Token=prefixstable:2002:da8:1::</programlisting></para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>UseDNS=</varname></term> + <listitem> + <para>When true (the default), the DNS servers received in the Router Advertisement will be used.</para> + + <para>This corresponds to the <option>nameserver</option> option in <citerefentry + project='man-pages'><refentrytitle>resolv.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>UseDomains=</varname></term> + <listitem> + <para>Takes a boolean, or the special value <literal>route</literal>. When true, the domain name + received via IPv6 Router Advertisement (RA) will be used as DNS search domain over this link, + similarly to the effect of the <option>Domains=</option> setting. If set to + <literal>route</literal>, the domain name received via IPv6 RA will be used for routing DNS queries + only, but not for searching, similarly to the effect of the <option>Domains=</option> setting when + the argument is prefixed with <literal>~</literal>. Defaults to false.</para> + + <para>It is recommended to enable this option only on trusted networks, as setting this affects resolution + of all hostnames, in particular of single-label names. It is generally safer to use the supplied domain + only as routing domain, rather than as search domain, in order to not have it affect local resolution of + single-label names.</para> + + <para>When set to true, this setting corresponds to the <option>domain</option> option in <citerefentry + project='man-pages'><refentrytitle>resolv.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>RouteTable=<replaceable>num</replaceable></varname></term> + <listitem> + <para>The table identifier for the routes received in the Router Advertisement. Takes one of + predefined names <literal>default</literal>, <literal>main</literal>, and <literal>local</literal>, + and names defined in <varname>RouteTable=</varname> in + <citerefentry><refentrytitle>networkd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + or a number between 1…4294967295.</para> + + <para>When used in combination with <varname>VRF=</varname>, the VRF's routing table is + used when this parameter is not specified.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>RouteMetric=</varname></term> + <listitem> + <para>Set the routing metric for the routes received in the Router Advertisement. Takes an + unsigned integer in the range 0…4294967295. Defaults to 1024.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>UseMTU=</varname></term> + <listitem> + <para>Takes a boolean. When true, the MTU received in the Router Advertisement will be + used. Defaults to true.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>UseGateway=</varname></term> + <listitem> + <para>When true (the default), the router address will be configured as the default gateway. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>UseRoutePrefix=</varname></term> + <listitem> + <para>When true (the default), the routes corresponding to the route prefixes received in + the Router Advertisement will be configured.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>UseAutonomousPrefix=</varname></term> + <listitem> + <para>When true (the default), the autonomous prefix received in the Router Advertisement will be used and take + precedence over any statically configured ones.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>UseOnLinkPrefix=</varname></term> + <listitem> + <para>When true (the default), the onlink prefix received in the Router Advertisement will be + used and takes precedence over any statically configured ones.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>RouterDenyList=</varname></term> + <listitem> + <para>A whitespace-separated list of IPv6 router addresses. Each address can optionally + take a prefix length after <literal>/</literal>. Any information advertised by the listed + router is ignored.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>RouterAllowList=</varname></term> + <listitem> + <para>A whitespace-separated list of IPv6 router addresses. Each address can optionally + take a prefix length after <literal>/</literal>. Only information advertised by the listed + router is accepted. Note that if <varname>RouterAllowList=</varname> is configured then + <varname>RouterDenyList=</varname> is ignored.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>PrefixDenyList=</varname></term> + <listitem> + <para>A whitespace-separated list of IPv6 prefixes. Each prefix can optionally take its + prefix length after <literal>/</literal>. IPv6 prefixes supplied via router advertisements + in the list are ignored.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>PrefixAllowList=</varname></term> + <listitem> + <para>A whitespace-separated list of IPv6 prefixes. Each prefix can optionally take its + prefix length after <literal>/</literal>. IPv6 prefixes supplied via router advertisements + in the list are allowed. Note that if <varname>PrefixAllowList=</varname> is configured + then <varname>PrefixDenyList=</varname> is ignored.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>RouteDenyList=</varname></term> + <listitem> + <para>A whitespace-separated list of IPv6 route prefixes. Each prefix can optionally take + its prefix length after <literal>/</literal>. IPv6 route prefixes supplied via router + advertisements in the list are ignored.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>RouteAllowList=</varname></term> + <listitem> + <para>A whitespace-separated list of IPv6 route prefixes. Each prefix can optionally take + its prefix length after <literal>/</literal>. IPv6 route prefixes supplied via router + advertisements in the list are allowed. Note that if <varname>RouteAllowList=</varname> is + configured then <varname>RouteDenyList=</varname> is ignored.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>DHCPv6Client=</varname></term> + <listitem> + <para>Takes a boolean, or the special value <literal>always</literal>. When true, the + DHCPv6 client will be started in <literal>solicit</literal> mode if the RA has the + <literal>managed</literal> flag or <literal>information-request</literal> mode if the RA + lacks the <literal>managed</literal> flag but has the + <literal>other configuration</literal> flag. If set to <literal>always</literal>, the + DHCPv6 client will be started in <literal>solicit</literal> mode when an RA is received, + even if neither the <literal>managed</literal> nor the + <literal>other configuration</literal> flag is set in the RA. This will be ignored when + <varname>WithoutRA=</varname> in the [DHCPv6] section is enabled, or + <varname>UplinkInterface=:self</varname> in the [DHCPPrefixDelegation] section is + specified. Defaults to true.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>NetLabel=</varname></term> + <listitem> + <para>This applies the NetLabel for the addresses received with RA, like + <varname>NetLabel=</varname> in [Address] section applies it to statically configured + addresses. See <varname>NetLabel=</varname> in [Address] section for more details.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[DHCPServer] Section Options</title> + <para>The [DHCPServer] section contains settings for the DHCP server, if enabled via the + <varname>DHCPServer=</varname> option described above:</para> + + <variablelist class='network-directives'> + + <varlistentry> + <term><varname>ServerAddress=</varname></term> + <listitem><para>Specifies server address for the DHCP server. Takes an IPv4 address with prefix + length, for example 192.168.0.1/24. This setting may be useful when the link on + which the DHCP server is running has multiple static addresses. When unset, one of static addresses + in the link will be automatically selected. Defaults to unset.</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>PoolOffset=</varname></term> + <term><varname>PoolSize=</varname></term> + + <listitem><para>Configures the pool of addresses to hand out. The pool + is a contiguous sequence of IP addresses in the subnet configured for + the server address, which does not include the subnet nor the broadcast + address. <varname>PoolOffset=</varname> takes the offset of the pool + from the start of subnet, or zero to use the default value. + <varname>PoolSize=</varname> takes the number of IP addresses in the + pool or zero to use the default value. By default, the pool starts at + the first address after the subnet address and takes up the rest of + the subnet, excluding the broadcast address. If the pool includes + the server address (the default), this is reserved and not handed + out to clients.</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>DefaultLeaseTimeSec=</varname></term> + <term><varname>MaxLeaseTimeSec=</varname></term> + + <listitem><para>Control the default and maximum DHCP lease + time to pass to clients. These settings take time values in seconds or + another common time unit, depending on the suffix. The default + lease time is used for clients that did not ask for a specific + lease time. If a client asks for a lease time longer than the + maximum lease time, it is automatically shortened to the + specified time. The default lease time defaults to 1h, the + maximum lease time to 12h. Shorter lease times are beneficial + if the configuration data in DHCP leases changes frequently + and clients shall learn the new settings with shorter + latencies. Longer lease times reduce the generated DHCP + network traffic.</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>UplinkInterface=</varname></term> + <listitem><para>Specifies the name or the index of the uplink interface, or one of the special + values <literal>:none</literal> and <literal>:auto</literal>. When emitting DNS, NTP, or SIP + servers is enabled but no servers are specified, the servers configured in the uplink interface + will be emitted. When <literal>:auto</literal>, the link which has a default gateway with the + highest priority will be automatically selected. When <literal>:none</literal>, no uplink + interface will be selected. Defaults to <literal>:auto</literal>.</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>EmitDNS=</varname></term> + <term><varname>DNS=</varname></term> + + <listitem><para><varname>EmitDNS=</varname> takes a boolean. Configures whether the DHCP leases + handed out to clients shall contain DNS server information. Defaults to <literal>yes</literal>. + The DNS servers to pass to clients may be configured with the <varname>DNS=</varname> option, + which takes a list of IPv4 addresses, or special value <literal>_server_address</literal> which + will be converted to the address used by the DHCP server.</para> + + <para>If the <varname>EmitDNS=</varname> option is enabled but no servers configured, the + servers are automatically propagated from an "uplink" interface that has appropriate servers + set. The "uplink" interface is determined by the default route of the system with the highest + priority. Note that this information is acquired at the time the lease is handed out, and does + not take uplink interfaces into account that acquire DNS server information at a later point. + If no suitable uplink interface is found the DNS server data from + <filename>/etc/resolv.conf</filename> is used. Also, note that the leases are not refreshed if + the uplink network configuration changes. To ensure clients regularly acquire the most current + uplink DNS server information, it is thus advisable to shorten the DHCP lease time via + <varname>MaxLeaseTimeSec=</varname> described above.</para> + + <para>This setting can be specified multiple times. If an empty string is specified, then all + DNS servers specified earlier are cleared.</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>EmitNTP=</varname></term> + <term><varname>NTP=</varname></term> + <term><varname>EmitSIP=</varname></term> + <term><varname>SIP=</varname></term> + <term><varname>EmitPOP3=</varname></term> + <term><varname>POP3=</varname></term> + <term><varname>EmitSMTP=</varname></term> + <term><varname>SMTP=</varname></term> + <term><varname>EmitLPR=</varname></term> + <term><varname>LPR=</varname></term> + + <listitem><para>Similar to the <varname>EmitDNS=</varname> and <varname>DNS=</varname> settings + described above, these settings configure whether and what server information for the indicate + protocol shall be emitted as part of the DHCP lease. The same syntax, propagation semantics and + defaults apply as for <varname>EmitDNS=</varname> and <varname>DNS=</varname>.</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>EmitRouter=</varname></term> + <term><varname>Router=</varname></term> + + <listitem><para>The <varname>EmitRouter=</varname> setting takes a boolean value, and configures + whether the DHCP lease should contain the router option. The <varname>Router=</varname> setting + takes an IPv4 address, and configures the router address to be emitted. When the + <varname>Router=</varname> setting is not specified, then the server address will be used for + the router option. When the <varname>EmitRouter=</varname> setting is disabled, the + <varname>Router=</varname> setting will be ignored. The <varname>EmitRouter=</varname> setting + defaults to true, and the <varname>Router=</varname> setting defaults to unset. + </para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>EmitTimezone=</varname></term> + <term><varname>Timezone=</varname></term> + + <listitem><para>Takes a boolean. Configures whether the DHCP leases handed out + to clients shall contain timezone information. Defaults to <literal>yes</literal>. The + <varname>Timezone=</varname> setting takes a timezone string + (such as <literal>Europe/Berlin</literal> or + <literal>UTC</literal>) to pass to clients. If no explicit + timezone is set, the system timezone of the local host is + propagated, as determined by the + <filename>/etc/localtime</filename> symlink.</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>BootServerAddress=</varname></term> + + <listitem> + <para>Takes an IPv4 address of the boot server used by e.g. PXE boot systems. When specified, this + address is sent in the <option>siaddr</option> field of the DHCP message header. See <ulink + url="https://www.rfc-editor.org/rfc/rfc2131.html">RFC 2131</ulink> for more details. Defaults to + unset.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>BootServerName=</varname></term> + + <listitem> + <para>Takes a name of the boot server used by e.g. PXE boot systems. When specified, this name is + sent in the DHCP option 66 ("TFTP server name"). See <ulink + url="https://www.rfc-editor.org/rfc/rfc2132.html">RFC 2132</ulink> for more details. Defaults to + unset.</para> + + <para>Note that typically setting one of <varname>BootServerName=</varname> or + <varname>BootServerAddress=</varname> is sufficient, but both can be set too, if desired.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>BootFilename=</varname></term> + + <listitem> + <para>Takes a path or URL to a file loaded by e.g. a PXE boot loader. When specified, this path is + sent in the DHCP option 67 ("Bootfile name"). See <ulink + url="https://www.rfc-editor.org/rfc/rfc2132.html">RFC 2132</ulink> for more details. Defaults to + unset.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>SendOption=</varname></term> + <listitem> + <para>Send a raw option with value via DHCPv4 server. Takes a DHCP option number, data type + and data (<literal><replaceable>option</replaceable>:<replaceable>type</replaceable>:<replaceable>value</replaceable></literal>). + The option number is an integer in the range 1…254. The type takes one of <literal>uint8</literal>, + <literal>uint16</literal>, <literal>uint32</literal>, <literal>ipv4address</literal>, <literal>ipv6address</literal>, or + <literal>string</literal>. Special characters in the data string may be escaped using + <ulink url="https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style + escapes</ulink>. This setting can be specified multiple times. If an empty string is specified, + then all options specified earlier are cleared. Defaults to unset.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>SendVendorOption=</varname></term> + <listitem> + <para>Send a vendor option with value via DHCPv4 server. Takes a DHCP option number, data type + and data (<literal><replaceable>option</replaceable>:<replaceable>type</replaceable>:<replaceable>value</replaceable></literal>). + The option number is an integer in the range 1…254. The type takes one of <literal>uint8</literal>, + <literal>uint16</literal>, <literal>uint32</literal>, <literal>ipv4address</literal>, or + <literal>string</literal>. Special characters in the data string may be escaped using + <ulink url="https://en.wikipedia.org/wiki/Escape_sequences_in_C#Table_of_escape_sequences">C-style + escapes</ulink>. This setting can be specified multiple times. If an empty string is specified, + then all options specified earlier are cleared. Defaults to unset.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>BindToInterface=</varname></term> + <listitem> + <para>Takes a boolean value. When <literal>yes</literal>, DHCP server socket will be bound + to its network interface and all socket communication will be restricted to this interface. + Defaults to <literal>yes</literal>, except if <varname>RelayTarget=</varname> is used (see below), + in which case it defaults to <literal>no</literal>.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>RelayTarget=</varname></term> + <listitem> + <para>Takes an IPv4 address, which must be in the format described in + <citerefentry project='man-pages'><refentrytitle>inet_pton</refentrytitle><manvolnum>3</manvolnum></citerefentry>. + Turns this DHCP server into a DHCP relay agent. See <ulink url="https://tools.ietf.org/html/rfc1542">RFC 1542</ulink>. + The address is the address of DHCP server or another relay agent to forward DHCP messages to and from.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>RelayAgentCircuitId=</varname></term> + <listitem> + <para>Specifies value for Agent Circuit ID suboption of Relay Agent Information option. + Takes a string, which must be in the format <literal>string:<replaceable>value</replaceable></literal>, + where <literal><replaceable>value</replaceable></literal> should be replaced with the value of the suboption. + Defaults to unset (means no Agent Circuit ID suboption is generated). + Ignored if <varname>RelayTarget=</varname> is not specified.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>RelayAgentRemoteId=</varname></term> + <listitem> + <para>Specifies value for Agent Remote ID suboption of Relay Agent Information option. + Takes a string, which must be in the format <literal>string:<replaceable>value</replaceable></literal>, + where <literal><replaceable>value</replaceable></literal> should be replaced with the value of the suboption. + Defaults to unset (means no Agent Remote ID suboption is generated). + Ignored if <varname>RelayTarget=</varname> is not specified.</para> + </listitem> + </varlistentry> + + </variablelist> + </refsect1> + + <refsect1> + <title>[DHCPServerStaticLease] Section Options</title> + <para>The <literal>[DHCPServerStaticLease]</literal> section configures a static DHCP lease to assign a + fixed IPv4 address to a specific device based on its MAC address. This section can be specified multiple + times.</para> + + <variablelist class='network-directives'> + <varlistentry> + <term><varname>MACAddress=</varname></term> + + <listitem><para>The hardware address of a device to match. This key is mandatory.</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>Address=</varname></term> + + <listitem><para>The IPv4 address that should be assigned to the device that was matched with + <varname>MACAddress=</varname>. This key is mandatory.</para></listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[IPv6SendRA] Section Options</title> + <para>The [IPv6SendRA] section contains settings for sending IPv6 Router Advertisements and whether + to act as a router, if enabled via the <varname>IPv6SendRA=</varname> option described above. IPv6 + network prefixes or routes are defined with one or more [IPv6Prefix] or [IPv6RoutePrefix] sections. + </para> + + <variablelist class='network-directives'> + + <varlistentry> + <term><varname>Managed=</varname></term> + <term><varname>OtherInformation=</varname></term> + + <listitem><para>Takes a boolean. Controls whether a DHCPv6 server is used to acquire IPv6 + addresses on the network link when <varname>Managed=</varname> + is set to <literal>true</literal> or if only additional network + information can be obtained via DHCPv6 for the network link when + <varname>OtherInformation=</varname> is set to + <literal>true</literal>. Both settings default to + <literal>false</literal>, which means that a DHCPv6 server is not being + used.</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>RouterLifetimeSec=</varname></term> + + <listitem><para>Takes a timespan. Configures the IPv6 router lifetime in seconds. The value must be 0 + seconds, or between 4 seconds and 9000 seconds. When set to 0, the host is not acting as a router. + Defaults to 1800 seconds (30 minutes).</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>RouterPreference=</varname></term> + + <listitem><para>Configures IPv6 router preference if + <varname>RouterLifetimeSec=</varname> is non-zero. Valid values are + <literal>high</literal>, <literal>medium</literal> and + <literal>low</literal>, with <literal>normal</literal> and + <literal>default</literal> added as synonyms for + <literal>medium</literal> just to make configuration easier. See + <ulink url="https://tools.ietf.org/html/rfc4191">RFC 4191</ulink> + for details. Defaults to <literal>medium</literal>.</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>UplinkInterface=</varname></term> + <listitem><para>Specifies the name or the index of the uplink interface, or one of the special + values <literal>:none</literal> and <literal>:auto</literal>. When emitting DNS servers or + search domains is enabled but no servers are specified, the servers configured in the uplink + interface will be emitted. When <literal>:auto</literal>, the value specified to the same + setting in the [DHCPPrefixDelegation] section will be used if + <varname>DHCPPrefixDelegation=</varname> is enabled, otherwise the link which has a default + gateway with the highest priority will be automatically selected. When <literal>:none</literal>, + no uplink interface will be selected. Defaults to <literal>:auto</literal>.</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>EmitDNS=</varname></term> + <term><varname>DNS=</varname></term> + + <listitem><para><varname>DNS=</varname> specifies a list of recursive DNS server IPv6 addresses + that are distributed via Router Advertisement messages when <varname>EmitDNS=</varname> is true. + <varname>DNS=</varname> also takes special value <literal>_link_local</literal>; in that case + the IPv6 link-local address is distributed. If <varname>DNS=</varname> is empty, DNS servers are + read from the [Network] section. If the [Network] section does not contain any DNS servers + either, DNS servers from the uplink interface specified in <varname>UplinkInterface=</varname> + will be used. When <varname>EmitDNS=</varname> is false, no DNS server information is sent in + Router Advertisement messages. <varname>EmitDNS=</varname> defaults to true.</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>EmitDomains=</varname></term> + <term><varname>Domains=</varname></term> + + <listitem><para>A list of DNS search domains distributed via Router Advertisement messages when + <varname>EmitDomains=</varname> is true. If <varname>Domains=</varname> is empty, DNS search + domains are read from the [Network] section. If the [Network] section does not contain any DNS + search domains either, DNS search domains from the uplink interface specified in + <varname>UplinkInterface=</varname> will be used. When <varname>EmitDomains=</varname> is false, + no DNS search domain information is sent in Router Advertisement messages. + <varname>EmitDomains=</varname> defaults to true.</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>DNSLifetimeSec=</varname></term> + + <listitem><para>Lifetime in seconds for the DNS server addresses listed in + <varname>DNS=</varname> and search domains listed in <varname>Domains=</varname>. Defaults to + 3600 seconds (one hour).</para></listitem> + </varlistentry> + + </variablelist> + </refsect1> + + <refsect1> + <title>[IPv6Prefix] Section Options</title> + <para>One or more [IPv6Prefix] sections contain the IPv6 prefixes that are announced via Router + Advertisements. See <ulink url="https://tools.ietf.org/html/rfc4861">RFC 4861</ulink> for further + details.</para> + + <variablelist class='network-directives'> + + <varlistentry> + <term><varname>AddressAutoconfiguration=</varname></term> + <term><varname>OnLink=</varname></term> + + <listitem><para>Takes a boolean to specify whether IPv6 addresses can be + autoconfigured with this prefix and whether the prefix can be used for + onlink determination. Both settings default to <literal>true</literal> + in order to ease configuration. + </para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>Prefix=</varname></term> + + <listitem><para>The IPv6 prefix that is to be distributed to hosts. Similarly to configuring static + IPv6 addresses, the setting is configured as an IPv6 prefix and its prefix length, separated by a + <literal>/</literal> character. Use multiple [IPv6Prefix] sections to configure multiple IPv6 + prefixes since prefix lifetimes, address autoconfiguration and onlink status may differ from one + prefix to another.</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>PreferredLifetimeSec=</varname></term> + <term><varname>ValidLifetimeSec=</varname></term> + + <listitem><para>Preferred and valid lifetimes for the prefix measured in seconds. + <varname>PreferredLifetimeSec=</varname> defaults to 1800 seconds (30 minutes) and + <varname>ValidLifetimeSec=</varname> defaults to 3600 seconds (one hour).</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>Assign=</varname></term> + <listitem><para>Takes a boolean. When true, adds an address from the prefix. Default to false. + </para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>Token=</varname></term> + <listitem> + <para>Specifies an optional address generation mode for assigning an address in each + prefix. This accepts the same syntax as <varname>Token=</varname> in the [IPv6AcceptRA] + section. If <varname>Assign=</varname> is set to false, then this setting will be ignored. + Defaults to unset, which means the EUI-64 algorithm will be used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>RouteMetric=</varname></term> + <listitem> + <para>The metric of the prefix route. Takes an unsigned integer in the range 0…4294967295. + When unset or set to 0, the kernel's default value is used. This setting is ignored when + <varname>Assign=</varname> is false.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[IPv6RoutePrefix] Section Options</title> + <para>One or more [IPv6RoutePrefix] sections contain the IPv6 + prefix routes that are announced via Router Advertisements. See + <ulink url="https://tools.ietf.org/html/rfc4191">RFC 4191</ulink> + for further details.</para> + + <variablelist class='network-directives'> + + <varlistentry> + <term><varname>Route=</varname></term> + + <listitem><para>The IPv6 route that is to be distributed to hosts. Similarly to configuring static + IPv6 routes, the setting is configured as an IPv6 prefix routes and its prefix route length, + separated by a <literal>/</literal> character. Use multiple [IPv6RoutePrefix] sections to configure + multiple IPv6 prefix routes.</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>LifetimeSec=</varname></term> + + <listitem><para>Lifetime for the route prefix measured in seconds. + <varname>LifetimeSec=</varname> defaults to 3600 seconds (one hour).</para></listitem> + </varlistentry> + + </variablelist> + </refsect1> + + <refsect1> + <title>[Bridge] Section Options</title> + <para>The [Bridge] section accepts the following keys:</para> + <variablelist class='network-directives'> + <varlistentry> + <term><varname>UnicastFlood=</varname></term> + <listitem> + <para>Takes a boolean. Controls whether the bridge should flood + traffic for which an FDB entry is missing and the destination + is unknown through this port. When unset, the kernel's default will be used. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>MulticastFlood=</varname></term> + <listitem> + <para>Takes a boolean. Controls whether the bridge should flood + traffic for which an MDB entry is missing and the destination + is unknown through this port. When unset, the kernel's default will be used. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>MulticastToUnicast=</varname></term> + <listitem> + <para>Takes a boolean. Multicast to unicast works on top of the multicast snooping feature of + the bridge. Which means unicast copies are only delivered to hosts which are interested in it. + When unset, the kernel's default will be used. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>NeighborSuppression=</varname></term> + <listitem> + <para>Takes a boolean. Configures whether ARP and ND neighbor suppression is enabled for + this port. When unset, the kernel's default will be used. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>Learning=</varname></term> + <listitem> + <para>Takes a boolean. Configures whether MAC address learning is enabled for + this port. When unset, the kernel's default will be used. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>HairPin=</varname></term> + <listitem> + <para>Takes a boolean. Configures whether traffic may be sent back out of the port on which it + was received. When this flag is false, then the bridge will not forward traffic back out of the + receiving port. When unset, the kernel's default will be used.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>Isolated=</varname></term> + <listitem> + <para>Takes a boolean. Configures whether this port is isolated or not. Within a bridge, + isolated ports can only communicate with non-isolated ports. When set to true, this port can only + communicate with other ports whose Isolated setting is false. When set to false, this port + can communicate with any other ports. When unset, the kernel's default will be used.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>UseBPDU=</varname></term> + <listitem> + <para>Takes a boolean. Configures whether STP Bridge Protocol Data Units will be + processed by the bridge port. When unset, the kernel's default will be used.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>FastLeave=</varname></term> + <listitem> + <para>Takes a boolean. This flag allows the bridge to immediately stop multicast + traffic on a port that receives an IGMP Leave message. It is only used with + IGMP snooping if enabled on the bridge. When unset, the kernel's default will be used.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>AllowPortToBeRoot=</varname></term> + <listitem> + <para>Takes a boolean. Configures whether a given port is allowed to + become a root port. Only used when STP is enabled on the bridge. + When unset, the kernel's default will be used.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>ProxyARP=</varname></term> + <listitem> + <para>Takes a boolean. Configures whether proxy ARP to be enabled on this port. + When unset, the kernel's default will be used.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>ProxyARPWiFi=</varname></term> + <listitem> + <para>Takes a boolean. Configures whether proxy ARP to be enabled on this port + which meets extended requirements by IEEE 802.11 and Hotspot 2.0 specifications. + When unset, the kernel's default will be used.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>MulticastRouter=</varname></term> + <listitem> + <para>Configures this port for having multicast routers attached. A port with a multicast + router will receive all multicast traffic. Takes one of <literal>no</literal> + to disable multicast routers on this port, <literal>query</literal> to let the system detect + the presence of routers, <literal>permanent</literal> to permanently enable multicast traffic + forwarding on this port, or <literal>temporary</literal> to enable multicast routers temporarily + on this port, not depending on incoming queries. When unset, the kernel's default will be used.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>Cost=</varname></term> + <listitem> + <para>Sets the "cost" of sending packets of this interface. + Each port in a bridge may have a different speed and the cost + is used to decide which link to use. Faster interfaces + should have lower costs. It is an integer value between 1 and + 65535.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>Priority=</varname></term> + <listitem> + <para>Sets the "priority" of sending packets on this interface. + Each port in a bridge may have a different priority which is used + to decide which link to use. Lower value means higher priority. + It is an integer value between 0 to 63. Networkd does not set any + default, meaning the kernel default value of 32 is used.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + <refsect1> + <title>[BridgeFDB] Section Options</title> + <para>The [BridgeFDB] section manages the forwarding database table of a port and accepts the following + keys. Specify several [BridgeFDB] sections to configure several static MAC table entries.</para> + + <variablelist class='network-directives'> + <varlistentry> + <term><varname>MACAddress=</varname></term> + <listitem> + <para>As in the [Network] section. This key is mandatory.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>Destination=</varname></term> + <listitem> + <para>Takes an IP address of the destination VXLAN tunnel endpoint.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>VLANId=</varname></term> + <listitem> + <para>The VLAN ID for the new static MAC table entry. If + omitted, no VLAN ID information is appended to the new static MAC + table entry.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>VNI=</varname></term> + <listitem> + <para>The VXLAN Network Identifier (or VXLAN Segment ID) to use to connect to + the remote VXLAN tunnel endpoint. Takes a number in the range 1…16777215. + Defaults to unset.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>AssociatedWith=</varname></term> + <listitem> + <para>Specifies where the address is associated with. Takes one of <literal>use</literal>, + <literal>self</literal>, <literal>master</literal> or <literal>router</literal>. + <literal>use</literal> means the address is in use. User space can use this option to + indicate to the kernel that the fdb entry is in use. <literal>self</literal> means + the address is associated with the port drivers fdb. Usually hardware. <literal>master</literal> + means the address is associated with master devices fdb. <literal>router</literal> means + the destination address is associated with a router. Note that it's valid if the referenced + device is a VXLAN type device and has route shortcircuit enabled. Defaults to <literal>self</literal>.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>OutgoingInterface=</varname></term> + <listitem> + <para>Specifies the name or index of the outgoing interface for the VXLAN device driver to + reach the remote VXLAN tunnel endpoint. Defaults to unset.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + <refsect1> + <title>[BridgeMDB] Section Options</title> + <para>The [BridgeMDB] section manages the multicast membership entries forwarding database table of a port and accepts the following + keys. Specify several [BridgeMDB] sections to configure several permanent multicast membership entries.</para> + + <variablelist class='network-directives'> + <varlistentry> + <term><varname>MulticastGroupAddress=</varname></term> + <listitem> + <para>Specifies the IPv4 or IPv6 multicast group address to add. This setting is mandatory.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>VLANId=</varname></term> + <listitem> + <para>The VLAN ID for the new entry. Valid ranges are 0 (no VLAN) to 4094. Optional, defaults to 0.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[LLDP] Section Options</title> + <para>The [LLDP] section manages the Link Layer Discovery Protocol (LLDP) and accepts the following + keys:</para> + <variablelist class='network-directives'> + <varlistentry> + <term><varname>MUDURL=</varname></term> + <listitem> + <para>When configured, the specified Manufacturer Usage Descriptions (MUD) URL will be sent in + LLDP packets. The syntax and semantics are the same as for <varname>MUDURL=</varname> in the + [DHCPv4] section described above.</para> + + <para>The MUD URLs received via LLDP packets are saved and can be read using the + <function>sd_lldp_neighbor_get_mud_url()</function> function.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[CAN] Section Options</title> + <para>The [CAN] section manages the Controller Area Network (CAN bus) and accepts the + following keys:</para> + <variablelist class='network-directives'> + <varlistentry> + <term><varname>BitRate=</varname></term> + <listitem> + <para>The bitrate of CAN device in bits per second. The usual SI prefixes (K, M) with the base of 1000 can + be used here. Takes a number in the range 1…4294967295.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>SamplePoint=</varname></term> + <listitem> + <para>Optional sample point in percent with one decimal (e.g. <literal>75%</literal>, + <literal>87.5%</literal>) or permille (e.g. <literal>875‰</literal>). This will be ignored when + <varname>BitRate=</varname> is unspecified.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>TimeQuantaNSec=</varname></term> + <term><varname>PropagationSegment=</varname></term> + <term><varname>PhaseBufferSegment1=</varname></term> + <term><varname>PhaseBufferSegment2=</varname></term> + <term><varname>SyncJumpWidth=</varname></term> + <listitem> + <para>Specifies the time quanta, propagation segment, phase buffer segment 1 and 2, and the + synchronization jump width, which allow one to define the CAN bit-timing in a hardware + independent format as proposed by the Bosch CAN 2.0 Specification. + <varname>TimeQuantaNSec=</varname> takes a timespan in nanoseconds. + <varname>PropagationSegment=</varname>, <varname>PhaseBufferSegment1=</varname>, + <varname>PhaseBufferSegment2=</varname>, and <varname>SyncJumpWidth=</varname> take number + of time quantum specified in <varname>TimeQuantaNSec=</varname> and must be an unsigned + integer in the range 0…4294967295. These settings except for + <varname>SyncJumpWidth=</varname> will be ignored when <varname>BitRate=</varname> is + specified.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>DataBitRate=</varname></term> + <term><varname>DataSamplePoint=</varname></term> + <listitem> + <para>The bitrate and sample point for the data phase, if CAN-FD is used. These settings are + analogous to the <varname>BitRate=</varname> and <varname>SamplePoint=</varname> keys.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>DataTimeQuantaNSec=</varname></term> + <term><varname>DataPropagationSegment=</varname></term> + <term><varname>DataPhaseBufferSegment1=</varname></term> + <term><varname>DataPhaseBufferSegment2=</varname></term> + <term><varname>DataSyncJumpWidth=</varname></term> + <listitem> + <para>Specifies the time quanta, propagation segment, phase buffer segment 1 and 2, and the + synchronization jump width for the data phase, if CAN-FD is used. These settings are + analogous to the <varname>TimeQuantaNSec=</varname> or related settings.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>FDMode=</varname></term> + <listitem> + <para>Takes a boolean. When <literal>yes</literal>, CAN-FD mode is enabled for the interface. + Note, that a bitrate and optional sample point should also be set for the CAN-FD data phase using + the <varname>DataBitRate=</varname> and <varname>DataSamplePoint=</varname> keys, or + <varname>DataTimeQuanta=</varname> and related settings.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>FDNonISO=</varname></term> + <listitem> + <para>Takes a boolean. When <literal>yes</literal>, non-ISO CAN-FD mode is enabled for the + interface. When unset, the kernel's default will be used.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>RestartSec=</varname></term> + <listitem> + <para>Automatic restart delay time. If set to a non-zero value, a restart of the CAN controller will be + triggered automatically in case of a bus-off condition after the specified delay time. Subsecond delays can + be specified using decimals (e.g. <literal>0.1s</literal>) or a <literal>ms</literal> or + <literal>us</literal> postfix. Using <literal>infinity</literal> or <literal>0</literal> will turn the + automatic restart off. By default automatic restart is disabled.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>Termination=</varname></term> + <listitem> + <para>Takes a boolean or a termination resistor value in ohm in the range 0…65535. When + <literal>yes</literal>, the termination resistor is set to 120 ohm. When + <literal>no</literal> or <literal>0</literal> is set, the termination resistor is disabled. + When unset, the kernel's default will be used.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>TripleSampling=</varname></term> + <listitem> + <para>Takes a boolean. When <literal>yes</literal>, three samples (instead of one) are used to determine + the value of a received bit by majority rule. When unset, the kernel's default will be used.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>BusErrorReporting=</varname></term> + <listitem> + <para>Takes a boolean. When <literal>yes</literal>, reporting of CAN bus errors is activated + (those include single bit, frame format, and bit stuffing errors, unable to send dominant bit, + unable to send recessive bit, bus overload, active error announcement, error occurred on + transmission). When unset, the kernel's default will be used. Note: in case of a CAN bus with a + single CAN device, sending a CAN frame may result in a huge number of CAN bus errors.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>ListenOnly=</varname></term> + <listitem> + <para>Takes a boolean. When <literal>yes</literal>, listen-only mode is enabled. When the + interface is in listen-only mode, the interface neither transmit CAN frames nor send ACK + bit. Listen-only mode is important to debug CAN networks without interfering with the + communication or acknowledge the CAN frame. When unset, the kernel's default will be used. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>Loopback=</varname></term> + <listitem> + <para>Takes a boolean. When <literal>yes</literal>, loopback mode is enabled. When the + loopback mode is enabled, the interface treats messages transmitted by itself as received + messages. The loopback mode is important to debug CAN networks. When unset, the kernel's + default will be used.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>OneShot=</varname></term> + <listitem> + <para>Takes a boolean. When <literal>yes</literal>, one-shot mode is enabled. When unset, + the kernel's default will be used.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>PresumeAck=</varname></term> + <listitem> + <para>Takes a boolean. When <literal>yes</literal>, the interface will ignore missing CAN + ACKs. When unset, the kernel's default will be used.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>ClassicDataLengthCode=</varname></term> + <listitem> + <para>Takes a boolean. When <literal>yes</literal>, the interface will handle the 4bit data + length code (DLC). When unset, the kernel's default will be used.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[IPoIB] Section Options</title> + <para>The [IPoIB] section manages the IP over Infiniband and accepts the following keys:</para> + <variablelist class='network-directives'> + <xi:include href="systemd.netdev.xml" xpointer="ipoib_mode" /> + <xi:include href="systemd.netdev.xml" xpointer="ipoib_umcast" /> + </variablelist> + </refsect1> + + <refsect1> + <title>[QDisc] Section Options</title> + <para>The [QDisc] section manages the traffic control queueing discipline (qdisc).</para> + + <variablelist class='network-directives'> + <varlistentry> + <term><varname>Parent=</varname></term> + <listitem> + <para>Specifies the parent Queueing Discipline (qdisc). Takes one of <literal>clsact</literal> + or <literal>ingress</literal>. This is mandatory.</para> + </listitem> + </varlistentry> + + <xi:include href="tc.xml" xpointer="qdisc-handle" /> + </variablelist> + </refsect1> + + <refsect1> + <title>[NetworkEmulator] Section Options</title> + <para>The [NetworkEmulator] section manages the queueing discipline (qdisc) of the network emulator. It + can be used to configure the kernel packet scheduler and simulate packet delay and loss for UDP or TCP + applications, or limit the bandwidth usage of a particular service to simulate internet connections. + </para> + + <variablelist class='network-directives'> + <xi:include href="tc.xml" xpointer="qdisc-parent" /> + <xi:include href="tc.xml" xpointer="qdisc-handle" /> + + <varlistentry> + <term><varname>DelaySec=</varname></term> + <listitem> + <para>Specifies the fixed amount of delay to be added to all packets going out of the + interface. Defaults to unset.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>DelayJitterSec=</varname></term> + <listitem> + <para>Specifies the chosen delay to be added to the packets outgoing to the network + interface. Defaults to unset.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>PacketLimit=</varname></term> + <listitem> + <para>Specifies the maximum number of packets the qdisc may hold queued at a time. + An unsigned integer in the range 0…4294967294. Defaults to 1000.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>LossRate=</varname></term> + <listitem> + <para>Specifies an independent loss probability to be added to the packets outgoing from the + network interface. Takes a percentage value, suffixed with "%". Defaults to unset.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>DuplicateRate=</varname></term> + <listitem> + <para>Specifies that the chosen percent of packets is duplicated before queuing them. + Takes a percentage value, suffixed with "%". Defaults to unset.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[TokenBucketFilter] Section Options</title> + <para>The [TokenBucketFilter] section manages the queueing discipline (qdisc) of token bucket filter + (tbf).</para> + + <variablelist class='network-directives'> + <xi:include href="tc.xml" xpointer="qdisc-parent" /> + <xi:include href="tc.xml" xpointer="qdisc-handle" /> + + <varlistentry> + <term><varname>LatencySec=</varname></term> + <listitem> + <para>Specifies the latency parameter, which specifies the maximum amount of time a + packet can sit in the Token Bucket Filter (TBF). Defaults to unset.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>LimitBytes=</varname></term> + <listitem> + <para>Takes the number of bytes that can be queued waiting for tokens to become available. + When the size is suffixed with K, M, or G, it is parsed as Kilobytes, Megabytes, or Gigabytes, + respectively, to the base of 1024. Defaults to unset.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>BurstBytes=</varname></term> + <listitem> + <para>Specifies the size of the bucket. This is the maximum amount of bytes that tokens + can be available for instantaneous transfer. When the size is suffixed with K, M, or G, it is + parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of 1024. Defaults to + unset.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Rate=</varname></term> + <listitem> + <para>Specifies the device specific bandwidth. When suffixed with K, M, or G, the specified + bandwidth is parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of 1000. + Defaults to unset.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>MPUBytes=</varname></term> + <listitem> + <para>The Minimum Packet Unit (MPU) determines the minimal token usage (specified in bytes) + for a packet. When suffixed with K, M, or G, the specified size is parsed as Kilobytes, + Megabytes, or Gigabytes, respectively, to the base of 1024. Defaults to zero.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>PeakRate=</varname></term> + <listitem> + <para>Takes the maximum depletion rate of the bucket. When suffixed with K, M, or G, the + specified size is parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of + 1000. Defaults to unset.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>MTUBytes=</varname></term> + <listitem> + <para>Specifies the size of the peakrate bucket. When suffixed with K, M, or G, the specified + size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of 1024. + Defaults to unset.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[PIE] Section Options</title> + <para>The [PIE] section manages the queueing discipline (qdisc) of Proportional Integral + controller-Enhanced (PIE).</para> + + <variablelist class='network-directives'> + <xi:include href="tc.xml" xpointer="qdisc-parent" /> + <xi:include href="tc.xml" xpointer="qdisc-handle" /> + + <varlistentry> + <term><varname>PacketLimit=</varname></term> + <listitem> + <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached, + incoming packets are dropped. An unsigned integer in the range 1…4294967294. Defaults to unset and + kernel's default is used.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[FlowQueuePIE] Section Options</title> + <para>The <literal>[FlowQueuePIE]</literal> section manages the queueing discipline + (qdisc) of Flow Queue Proportional Integral controller-Enhanced (fq_pie).</para> + + <variablelist class='network-directives'> + <xi:include href="tc.xml" xpointer="qdisc-parent" /> + <xi:include href="tc.xml" xpointer="qdisc-handle" /> + + <varlistentry> + <term><varname>PacketLimit=</varname></term> + <listitem> + <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached, + incoming packets are dropped. An unsigned integer ranges 1 to 4294967294. Defaults to unset and + kernel's default is used.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[StochasticFairBlue] Section Options</title> + <para>The [StochasticFairBlue] section manages the queueing discipline (qdisc) of stochastic fair blue + (sfb).</para> + + <variablelist class='network-directives'> + <xi:include href="tc.xml" xpointer="qdisc-parent" /> + <xi:include href="tc.xml" xpointer="qdisc-handle" /> + + <varlistentry> + <term><varname>PacketLimit=</varname></term> + <listitem> + <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached, + incoming packets are dropped. An unsigned integer in the range 0…4294967294. Defaults to unset and + kernel's default is used.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[StochasticFairnessQueueing] Section Options</title> + <para>The [StochasticFairnessQueueing] section manages the queueing discipline (qdisc) of stochastic + fairness queueing (sfq).</para> + + <variablelist class='network-directives'> + <xi:include href="tc.xml" xpointer="qdisc-parent" /> + <xi:include href="tc.xml" xpointer="qdisc-handle" /> + + <varlistentry> + <term><varname>PerturbPeriodSec=</varname></term> + <listitem> + <para>Specifies the interval in seconds for queue algorithm perturbation. Defaults to unset.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[BFIFO] Section Options</title> + <para>The [BFIFO] section manages the queueing discipline (qdisc) of Byte limited Packet First In First + Out (bfifo).</para> + + <variablelist class='network-directives'> + <xi:include href="tc.xml" xpointer="qdisc-parent" /> + <xi:include href="tc.xml" xpointer="qdisc-handle" /> + + <varlistentry> + <term><varname>LimitBytes=</varname></term> + <listitem> + <para>Specifies the hard limit in bytes on the FIFO buffer size. The size limit prevents overflow + in case the kernel is unable to dequeue packets as quickly as it receives them. When this limit is + reached, incoming packets are dropped. When suffixed with K, M, or G, the specified size is parsed + as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of 1024. Defaults to unset and + kernel default is used.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[PFIFO] Section Options</title> + <para>The [PFIFO] section manages the queueing discipline (qdisc) of Packet First In First Out + (pfifo).</para> + + <variablelist class='network-directives'> + <xi:include href="tc.xml" xpointer="qdisc-parent" /> + <xi:include href="tc.xml" xpointer="qdisc-handle" /> + + <varlistentry> + <term><varname>PacketLimit=</varname></term> + <listitem> + <para>Specifies the hard limit on the number of packets in the FIFO queue. The size limit prevents + overflow in case the kernel is unable to dequeue packets as quickly as it receives them. When this + limit is reached, incoming packets are dropped. An unsigned integer in the range + 0…4294967294. Defaults to unset and kernel's default is used.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[PFIFOHeadDrop] Section Options</title> + <para>The [PFIFOHeadDrop] section manages the queueing discipline (qdisc) of Packet First In First Out + Head Drop (pfifo_head_drop).</para> + + <variablelist class='network-directives'> + <xi:include href="tc.xml" xpointer="qdisc-parent" /> + <xi:include href="tc.xml" xpointer="qdisc-handle" /> + + <varlistentry> + <term><varname>PacketLimit=</varname></term> + <listitem> + <para>As in [PFIFO] section.</para></listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[PFIFOFast] Section Options</title> + <para>The [PFIFOFast] section manages the queueing discipline (qdisc) of Packet First In First Out Fast + (pfifo_fast).</para> + + <variablelist class='network-directives'> + <xi:include href="tc.xml" xpointer="qdisc-parent" /> + <xi:include href="tc.xml" xpointer="qdisc-handle" /> + </variablelist> + </refsect1> + + <refsect1> + <title>[CAKE] Section Options</title> + <para>The [CAKE] section manages the queueing discipline (qdisc) of Common Applications Kept Enhanced + (CAKE).</para> + + <variablelist class='network-directives'> + <xi:include href="tc.xml" xpointer="qdisc-parent" /> + <xi:include href="tc.xml" xpointer="qdisc-handle" /> + + <varlistentry> + <term><varname>Bandwidth=</varname></term> + <listitem> + <para>Specifies the shaper bandwidth. When suffixed with K, M, or G, the specified size is + parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of 1000. Defaults to + unset and kernel's default is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>AutoRateIngress=</varname></term> + <listitem> + <para>Takes a boolean value. Enables automatic capacity estimation based on traffic arriving + at this qdisc. This is most likely to be useful with cellular links, which tend to change + quality randomly. If this setting is enabled, the <varname>Bandwidth=</varname> setting is + used as an initial estimate. Defaults to unset, and the kernel's default is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>OverheadBytes=</varname></term> + <listitem> + <para>Specifies that bytes to be addeded to the size of each packet. Bytes may be negative. + Takes an integer in the range -64…256. Defaults to unset and kernel's default is used. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>MPUBytes=</varname></term> + <listitem> + <para>Rounds each packet (including overhead) up to the specified bytes. Takes an integer in + the range 1…256. Defaults to unset and kernel's default is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>CompensationMode=</varname></term> + <listitem> + <para>Takes one of <literal>none</literal>, <literal>atm</literal>, or <literal>ptm</literal>. + Specifies the compensation mode for overhead calculation. When <literal>none</literal>, no + compensation is taken into account. When <literal>atm</literal>, enables the compensation for + ATM cell framing, which is normally found on ADSL links. When <literal>ptm</literal>, enables + the compensation for PTM encoding, which is normally found on VDSL2 links and uses a 64b/65b + encoding scheme. Defaults to unset and the kernel's default is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>UseRawPacketSize=</varname></term> + <listitem> + <para>Takes a boolean value. When true, the packet size reported by the Linux kernel will be + used, instead of the underlying IP packet size. Defaults to unset, and the kernel's default + is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>FlowIsolationMode=</varname></term> + <listitem> + <para>CAKE places packets from different flows into different queues, then packets from each + queue are delivered fairly. This specifies whether the fairness is based on source address, + destination address, individual flows, or any combination of those. The available values are: + </para> + + <variablelist> + <varlistentry> + <term><option>none</option></term> + <listitem><para> + The flow isolation is disabled, and all traffic passes through a single queue. + </para></listitem> + </varlistentry> + <varlistentry> + <term><option>src-host</option></term> + <listitem><para> + Flows are defined only by source address. Equivalent to the <literal>srchost</literal> + option for <command>tc qdisc</command> command. See also + <citerefentry project='man-pages'><refentrytitle>tc-cake</refentrytitle><manvolnum>8</manvolnum></citerefentry>. + </para></listitem> + </varlistentry> + <varlistentry> + <term><option>dst-host</option></term> + <listitem><para> + Flows are defined only by destination address. Equivalent to the + <literal>dsthost</literal> option for <command>tc qdisc</command> command. See also + <citerefentry project='man-pages'><refentrytitle>tc-cake</refentrytitle><manvolnum>8</manvolnum></citerefentry>. + </para></listitem> + </varlistentry> + <varlistentry> + <term><option>hosts</option></term> + <listitem><para> + Flows are defined by source-destination host pairs. Equivalent to the same option for + <command>tc qdisc</command> command. See also + <citerefentry project='man-pages'><refentrytitle>tc-cake</refentrytitle><manvolnum>8</manvolnum></citerefentry>. + </para></listitem> + </varlistentry> + <varlistentry> + <term><option>flows</option></term> + <listitem><para> + Flows are defined by the entire 5-tuple of source address, destination address, + transport protocol, source port and destination port. Equivalent to the same option for + <command>tc qdisc</command> command. See also + <citerefentry project='man-pages'><refentrytitle>tc-cake</refentrytitle><manvolnum>8</manvolnum></citerefentry>. + </para></listitem> + </varlistentry> + <varlistentry> + <term><option>dual-src-host</option></term> + <listitem><para> + Flows are defined by the 5-tuple (see <literal>flows</literal> in the above), and + fairness is applied first over source addresses, then over individual flows. Equivalent + to the <literal>dual-srchost</literal> option for <command>tc qdisc</command> command. + See also + <citerefentry project='man-pages'><refentrytitle>tc-cake</refentrytitle><manvolnum>8</manvolnum></citerefentry>. + </para></listitem> + </varlistentry> + <varlistentry> + <term><option>dual-dst-host</option></term> + <listitem><para> + Flows are defined by the 5-tuple (see <literal>flows</literal> in the above), and + fairness is applied first over destination addresses, then over individual flows. + Equivalent to the <literal>dual-dsthost</literal> option for + <command>tc qdisc</command> command. See also + <citerefentry project='man-pages'><refentrytitle>tc-cake</refentrytitle><manvolnum>8</manvolnum></citerefentry>. + </para></listitem> + </varlistentry> + <varlistentry> + <term><option>triple</option></term> + <listitem><para> + Flows are defined by the 5-tuple (see <literal>flows</literal>), and fairness is + applied over source and destination addresses, and also over individual flows. + Equivalent to the <literal>triple-isolate</literal> option for + <command>tc qdisc</command> command. See also + <citerefentry project='man-pages'><refentrytitle>tc-cake</refentrytitle><manvolnum>8</manvolnum></citerefentry>. + </para></listitem> + </varlistentry> + </variablelist> + + <para>Defaults to unset and the kernel's default is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>NAT=</varname></term> + <listitem> + <para>Takes a boolean value. When true, CAKE performs a NAT lookup before applying + flow-isolation rules, to determine the true addresses and port numbers of the packet, to + improve fairness between hosts inside the NAT. This has no practical effect when + <varname>FlowIsolationMode=</varname> is <literal>none</literal> or <literal>flows</literal>, + or if NAT is performed on a different host. Defaults to unset, and the kernel's default is + used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>PriorityQueueingPreset=</varname></term> + <listitem> + <para>CAKE divides traffic into <literal>tins</literal>, and each tin has its own independent + set of flow-isolation queues, bandwidth threshold, and priority. This specifies the preset of + tin profiles. The available values are:</para> + + <variablelist> + <varlistentry> + <term><option>besteffort</option></term> + <listitem><para> + Disables priority queueing by placing all traffic in one tin. + </para></listitem> + </varlistentry> + <varlistentry> + <term><option>precedence</option></term> + <listitem><para> + Enables priority queueing based on the legacy interpretation of TOS + <literal>Precedence</literal> field. Use of this preset on the modern Internet is + firmly discouraged. + </para></listitem> + </varlistentry> + <varlistentry> + <term><option>diffserv8</option></term> + <listitem><para> + Enables priority queueing based on the Differentiated Service + (<literal>DiffServ</literal>) field with eight tins: Background Traffic, High + Throughput, Best Effort, Video Streaming, Low Latency Transactions, Interactive Shell, + Minimum Latency, and Network Control. + </para></listitem> + </varlistentry> + <varlistentry> + <term><option>diffserv4</option></term> + <listitem><para> + Enables priority queueing based on the Differentiated Service + (<literal>DiffServ</literal>) field with four tins: Background Traffic, Best Effort, + Streaming Media, and Latency Sensitive. + </para></listitem> + </varlistentry> + <varlistentry> + <term><option>diffserv3</option></term> + <listitem><para> + Enables priority queueing based on the Differentiated Service + (<literal>DiffServ</literal>) field with three tins: Background Traffic, Best Effort, + and Latency Sensitive. + </para></listitem> + </varlistentry> + </variablelist> + + <para>Defaults to unset, and the kernel's default is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>FirewallMark=</varname></term> + <listitem> + <para>Takes an integer in the range 1…4294967295. When specified, firewall-mark-based + overriding of CAKE's tin selection is enabled. Defaults to unset, and the kernel's default is + used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Wash=</varname></term> + <listitem> + <para>Takes a boolean value. When true, CAKE clears the DSCP fields, except for ECN bits, of + any packet passing through CAKE. Defaults to unset, and the kernel's default is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>SplitGSO=</varname></term> + <listitem> + <para>Takes a boolean value. When true, CAKE will split General Segmentation Offload (GSO) + super-packets into their on-the-wire components and dequeue them individually. Defaults to + unset, and the kernel's default is used.</para> + </listitem> + </varlistentry> + + </variablelist> + </refsect1> + + <refsect1> + <title>[ControlledDelay] Section Options</title> + <para>The [ControlledDelay] section manages the queueing discipline (qdisc) of + controlled delay (CoDel).</para> + + <variablelist class='network-directives'> + <xi:include href="tc.xml" xpointer="qdisc-parent" /> + <xi:include href="tc.xml" xpointer="qdisc-handle" /> + + <varlistentry> + <term><varname>PacketLimit=</varname></term> + <listitem> + <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached, + incoming packets are dropped. An unsigned integer in the range 0…4294967294. Defaults to unset and + kernel's default is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>TargetSec=</varname></term> + <listitem> + <para>Takes a timespan. Specifies the acceptable minimum standing/persistent queue delay. + Defaults to unset and kernel's default is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>IntervalSec=</varname></term> + <listitem> + <para>Takes a timespan. This is used to ensure that the measured minimum delay does not + become too stale. Defaults to unset and kernel's default is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>ECN=</varname></term> + <listitem> + <para>Takes a boolean. This can be used to mark packets instead of dropping them. Defaults to + unset and kernel's default is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>CEThresholdSec=</varname></term> + <listitem> + <para>Takes a timespan. This sets a threshold above which all packets are marked with ECN + Congestion Experienced (CE). Defaults to unset and kernel's default is used.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[DeficitRoundRobinScheduler] Section Options</title> + <para>The [DeficitRoundRobinScheduler] section manages the queueing discipline (qdisc) of Deficit Round + Robin Scheduler (DRR).</para> + + <variablelist class='network-directives'> + <xi:include href="tc.xml" xpointer="qdisc-parent" /> + <xi:include href="tc.xml" xpointer="qdisc-handle" /> + </variablelist> + </refsect1> + + <refsect1> + <title>[DeficitRoundRobinSchedulerClass] Section Options</title> + <para>The [DeficitRoundRobinSchedulerClass] section manages the traffic control class of Deficit Round + Robin Scheduler (DRR).</para> + + <variablelist class='network-directives'> + <xi:include href="tc.xml" xpointer="tclass-parent" /> + <xi:include href="tc.xml" xpointer="tclass-classid" /> + + <varlistentry> + <term><varname>QuantumBytes=</varname></term> + <listitem> + <para>Specifies the amount of bytes a flow is allowed to dequeue before the scheduler moves + to the next class. When suffixed with K, M, or G, the specified size is parsed as Kilobytes, + Megabytes, or Gigabytes, respectively, to the base of 1024. Defaults to the MTU of the + interface.</para> + </listitem> + </varlistentry> + + </variablelist> + </refsect1> + + <refsect1> + <title>[EnhancedTransmissionSelection] Section Options</title> + <para>The [EnhancedTransmissionSelection] section manages the queueing discipline (qdisc) of Enhanced + Transmission Selection (ETS).</para> + + <variablelist class='network-directives'> + <xi:include href="tc.xml" xpointer="qdisc-parent" /> + <xi:include href="tc.xml" xpointer="qdisc-handle" /> + + <varlistentry> + <term><varname>Bands=</varname></term> + <listitem> + <para>Specifies the number of bands. An unsigned integer in the range 1…16. This value has to be at + least large enough to cover the strict bands specified through the <varname>StrictBands=</varname> + and bandwidth-sharing bands specified in <varname>QuantumBytes=</varname>.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>StrictBands=</varname></term> + <listitem> + <para>Specifies the number of bands that should be created in strict mode. An unsigned integer in + the range 1…16.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>QuantumBytes=</varname></term> + <listitem> + <para>Specifies the white-space separated list of quantum used in band-sharing bands. When + suffixed with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes, + respectively, to the base of 1024. This setting can be specified multiple times. If an empty + string is assigned, then the all previous assignments are cleared.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>PriorityMap=</varname></term> + <listitem> + <para>The priority map maps the priority of a packet to a band. The argument is a whitespace + separated list of numbers. The first number indicates which band the packets with priority 0 should + be put to, the second is for priority 1, and so on. There can be up to 16 numbers in the list. If + there are fewer, the default band that traffic with one of the unmentioned priorities goes to is + the last one. Each band number must be in the range 0…255. This setting can be specified multiple + times. If an empty string is assigned, then the all previous assignments are cleared.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[GenericRandomEarlyDetection] Section Options</title> + <para>The [GenericRandomEarlyDetection] section manages the queueing discipline (qdisc) of Generic Random + Early Detection (GRED).</para> + + <variablelist class='network-directives'> + <xi:include href="tc.xml" xpointer="qdisc-parent" /> + <xi:include href="tc.xml" xpointer="qdisc-handle" /> + + <varlistentry> + <term><varname>VirtualQueues=</varname></term> + <listitem> + <para>Specifies the number of virtual queues. Takes an integer in the range 1…16. Defaults to unset + and kernel's default is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>DefaultVirtualQueue=</varname></term> + <listitem> + <para>Specifies the number of default virtual queue. This must be less than <varname>VirtualQueue=</varname>. + Defaults to unset and kernel's default is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>GenericRIO=</varname></term> + <listitem> + <para>Takes a boolean. It turns on the RIO-like buffering scheme. Defaults to + unset and kernel's default is used.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[FairQueueingControlledDelay] Section Options</title> + <para>The [FairQueueingControlledDelay] section manages the queueing discipline (qdisc) of fair queuing + controlled delay (FQ-CoDel).</para> + + <variablelist class='network-directives'> + <xi:include href="tc.xml" xpointer="qdisc-parent" /> + <xi:include href="tc.xml" xpointer="qdisc-handle" /> + + <varlistentry> + <term><varname>PacketLimit=</varname></term> + <listitem> + <para>Specifies the hard limit on the real queue size. When this limit is reached, incoming packets are + dropped. Defaults to unset and kernel's default is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>MemoryLimitBytes=</varname></term> + <listitem> + <para>Specifies the limit on the total number of bytes that can be queued in this FQ-CoDel instance. + When suffixed with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes, + respectively, to the base of 1024. Defaults to unset and kernel's default is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Flows=</varname></term> + <listitem> + <para>Specifies the number of flows into which the incoming packets are classified. + Defaults to unset and kernel's default is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>TargetSec=</varname></term> + <listitem> + <para>Takes a timespan. Specifies the acceptable minimum standing/persistent queue delay. + Defaults to unset and kernel's default is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>IntervalSec=</varname></term> + <listitem> + <para>Takes a timespan. This is used to ensure that the measured minimum delay does not + become too stale. Defaults to unset and kernel's default is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>QuantumBytes=</varname></term> + <listitem> + <para>Specifies the number of bytes used as the "deficit" in the fair queuing algorithm timespan. + When suffixed with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes, + respectively, to the base of 1024. Defaults to unset and kernel's default is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>ECN=</varname></term> + <listitem> + <para>Takes a boolean. This can be used to mark packets instead of dropping them. Defaults to + unset and kernel's default is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>CEThresholdSec=</varname></term> + <listitem> + <para>Takes a timespan. This sets a threshold above which all packets are marked with ECN + Congestion Experienced (CE). Defaults to unset and kernel's default is used.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[FairQueueing] Section Options</title> + <para>The [FairQueueing] section manages the queueing discipline (qdisc) of fair queue traffic policing + (FQ).</para> + + <variablelist class='network-directives'> + <xi:include href="tc.xml" xpointer="qdisc-parent" /> + <xi:include href="tc.xml" xpointer="qdisc-handle" /> + + <varlistentry> + <term><varname>PacketLimit=</varname></term> + <listitem> + <para>Specifies the hard limit on the real queue size. When this limit is reached, incoming packets are + dropped. Defaults to unset and kernel's default is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>FlowLimit=</varname></term> + <listitem> + <para>Specifies the hard limit on the maximum number of packets queued per flow. Defaults to + unset and kernel's default is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>QuantumBytes=</varname></term> + <listitem> + <para>Specifies the credit per dequeue RR round, i.e. the amount of bytes a flow is allowed + to dequeue at once. When suffixed with K, M, or G, the specified size is parsed as Kilobytes, + Megabytes, or Gigabytes, respectively, to the base of 1024. Defaults to unset and kernel's + default is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>InitialQuantumBytes=</varname></term> + <listitem> + <para>Specifies the initial sending rate credit, i.e. the amount of bytes a new flow is + allowed to dequeue initially. When suffixed with K, M, or G, the specified size is parsed as + Kilobytes, Megabytes, or Gigabytes, respectively, to the base of 1024. Defaults to unset and + kernel's default is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>MaximumRate=</varname></term> + <listitem> + <para>Specifies the maximum sending rate of a flow. When suffixed with K, M, or G, the + specified size is parsed as Kilobits, Megabits, or Gigabits, respectively, to the base of + 1000. Defaults to unset and kernel's default is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Buckets=</varname></term> + <listitem> + <para>Specifies the size of the hash table used for flow lookups. Defaults to unset and + kernel's default is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>OrphanMask=</varname></term> + <listitem> + <para>Takes an unsigned integer. For packets not owned by a socket, fq is able to mask a part + of hash and reduce number of buckets associated with the traffic. Defaults to unset and + kernel's default is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Pacing=</varname></term> + <listitem> + <para>Takes a boolean, and enables or disables flow pacing. Defaults to unset and kernel's + default is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>CEThresholdSec=</varname></term> + <listitem> + <para>Takes a timespan. This sets a threshold above which all packets are marked with ECN + Congestion Experienced (CE). Defaults to unset and kernel's default is used.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[TrivialLinkEqualizer] Section Options</title> + <para>The [TrivialLinkEqualizer] section manages the queueing discipline (qdisc) of trivial link + equalizer (teql).</para> + + <variablelist class='network-directives'> + <xi:include href="tc.xml" xpointer="qdisc-parent" /> + <xi:include href="tc.xml" xpointer="qdisc-handle" /> + + <varlistentry> + <term><varname>Id=</varname></term> + <listitem> + <para>Specifies the interface ID <literal>N</literal> of teql. Defaults to <literal>0</literal>. + Note that when teql is used, currently, the module <constant>sch_teql</constant> with + <constant>max_equalizers=N+1</constant> option must be loaded before + <command>systemd-networkd</command> is started.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[HierarchyTokenBucket] Section Options</title> + <para>The [HierarchyTokenBucket] section manages the queueing discipline (qdisc) of hierarchy token + bucket (htb).</para> + + <variablelist class='network-directives'> + <xi:include href="tc.xml" xpointer="qdisc-parent" /> + <xi:include href="tc.xml" xpointer="qdisc-handle" /> + + <varlistentry> + <term><varname>DefaultClass=</varname></term> + <listitem> + <para>Takes the minor id in hexadecimal of the default class. Unclassified traffic gets sent + to the class. Defaults to unset.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>RateToQuantum=</varname></term> + <listitem> + <para>Takes an unsigned integer. The DRR quantums are calculated by dividing the value + configured in <varname>Rate=</varname> by <varname>RateToQuantum=</varname>.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[HierarchyTokenBucketClass] Section Options</title> + <para>The [HierarchyTokenBucketClass] section manages the traffic control class of hierarchy token bucket + (htb).</para> + + <variablelist class='network-directives'> + <xi:include href="tc.xml" xpointer="tclass-parent" /> + <xi:include href="tc.xml" xpointer="tclass-classid" /> + + <varlistentry> + <term><varname>Priority=</varname></term> + <listitem> + <para>Specifies the priority of the class. In the round-robin process, classes with the lowest + priority field are tried for packets first.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>QuantumBytes=</varname></term> + <listitem> + <para>Specifies how many bytes to serve from leaf at once. When suffixed with K, M, or G, the + specified size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of + 1024.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>MTUBytes=</varname></term> + <listitem> + <para>Specifies the maximum packet size we create. When suffixed with K, M, or G, the specified + size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of 1024.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>OverheadBytes=</varname></term> + <listitem> + <para>Takes an unsigned integer which specifies per-packet size overhead used in rate + computations. When suffixed with K, M, or G, the specified size is parsed as Kilobytes, + Megabytes, or Gigabytes, respectively, to the base of 1024.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>Rate=</varname></term> + <listitem> + <para>Specifies the maximum rate this class and all its children are guaranteed. When suffixed + with K, M, or G, the specified size is parsed as Kilobits, Megabits, or Gigabits, respectively, + to the base of 1000. This setting is mandatory.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>CeilRate=</varname></term> + <listitem> + <para>Specifies the maximum rate at which a class can send, if its parent has bandwidth to spare. + When suffixed with K, M, or G, the specified size is parsed as Kilobits, Megabits, or Gigabits, + respectively, to the base of 1000. When unset, the value specified with <varname>Rate=</varname> + is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>BufferBytes=</varname></term> + <listitem> + <para>Specifies the maximum bytes burst which can be accumulated during idle period. When suffixed + with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, + to the base of 1024.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>CeilBufferBytes=</varname></term> + <listitem> + <para>Specifies the maximum bytes burst for ceil which can be accumulated during idle period. + When suffixed with K, M, or G, the specified size is parsed as Kilobytes, Megabytes, or Gigabytes, + respectively, to the base of 1024.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[HeavyHitterFilter] Section Options</title> + <para>The [HeavyHitterFilter] section manages the queueing discipline (qdisc) of Heavy Hitter Filter + (hhf).</para> + + <variablelist class='network-directives'> + <xi:include href="tc.xml" xpointer="qdisc-parent" /> + <xi:include href="tc.xml" xpointer="qdisc-handle" /> + + <varlistentry> + <term><varname>PacketLimit=</varname></term> + <listitem> + <para>Specifies the hard limit on the queue size in number of packets. When this limit is reached, + incoming packets are dropped. An unsigned integer in the range 0…4294967294. Defaults to unset and + kernel's default is used.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[QuickFairQueueing] Section Options</title> + <para>The [QuickFairQueueing] section manages the queueing discipline (qdisc) of Quick Fair Queueing + (QFQ).</para> + + <variablelist class='network-directives'> + <xi:include href="tc.xml" xpointer="qdisc-parent" /> + <xi:include href="tc.xml" xpointer="qdisc-handle" /> + </variablelist> + </refsect1> + + <refsect1> + <title>[QuickFairQueueingClass] Section Options</title> + <para>The [QuickFairQueueingClass] section manages the traffic control class of Quick Fair Queueing + (qfq).</para> + + <variablelist class='network-directives'> + <xi:include href="tc.xml" xpointer="tclass-parent" /> + <xi:include href="tc.xml" xpointer="tclass-classid" /> + + <varlistentry> + <term><varname>Weight=</varname></term> + <listitem> + <para>Specifies the weight of the class. Takes an integer in the range 1…1023. Defaults to + unset in which case the kernel default is used.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>MaxPacketBytes=</varname></term> + <listitem> + <para>Specifies the maximum packet size in bytes for the class. When suffixed with K, M, or G, the + specified size is parsed as Kilobytes, Megabytes, or Gigabytes, respectively, to the base of + 1024. When unset, the kernel default is used.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[BridgeVLAN] Section Options</title> + <para>The [BridgeVLAN] section manages the VLAN ID configuration of a bridge port and accepts the + following keys. Specify several [BridgeVLAN] sections to configure several VLAN entries. The + <varname>VLANFiltering=</varname> option has to be enabled, see the [Bridge] section in + <citerefentry><refentrytitle>systemd.netdev</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para> + + <variablelist class='network-directives'> + <varlistentry> + <term><varname>VLAN=</varname></term> + <listitem> + <para>The VLAN ID allowed on the port. This can be either a single ID or a range M-N. Takes + an integer in the range 1…4094.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>EgressUntagged=</varname></term> + <listitem> + <para>The VLAN ID specified here will be used to untag frames on egress. Configuring + <varname>EgressUntagged=</varname> implicates the use of <varname>VLAN=</varname> above and will enable the + VLAN ID for ingress as well. This can be either a single ID or a range M-N.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>PVID=</varname></term> + <listitem> + <para>The Port VLAN ID specified here is assigned to all untagged frames at ingress. + <varname>PVID=</varname> can be used only once. Configuring <varname>PVID=</varname> implicates the use of + <varname>VLAN=</varname> above and will enable the VLAN ID for ingress as well.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Examples</title> + <example> + <title>Static network configuration</title> + + <programlisting># /etc/systemd/network/50-static.network +[Match] +Name=enp2s0 + +[Network] +Address=192.168.0.15/24 +Gateway=192.168.0.1</programlisting> + + <para>This brings interface <literal>enp2s0</literal> up with a static address. The + specified gateway will be used for a default route.</para> + </example> + + <example> + <title>DHCP on ethernet links</title> + + <programlisting># /etc/systemd/network/80-dhcp.network +[Match] +Name=en* + +[Network] +DHCP=yes</programlisting> + + <para>This will enable DHCPv4 and DHCPv6 on all interfaces with names starting with + <literal>en</literal> (i.e. ethernet interfaces).</para> + </example> + + <example> + <title>IPv6 Prefix Delegation (DHCPv6 PD)</title> + + <programlisting># /etc/systemd/network/55-dhcpv6-pd-upstream.network +[Match] +Name=enp1s0 + +[Network] +DHCP=ipv6 + +# The below setting is optional, to also assign an address in the delegated prefix +# to the upstream interface. If not necessary, then comment out the line below and +# the [DHCPPrefixDelegation] section. +DHCPPrefixDelegation=yes + +# If the upstream network provides Router Advertisement with Managed bit set, +# then comment out the line below and WithoutRA= setting in the [DHCPv6] section. +IPv6AcceptRA=no + +[DHCPv6] +WithoutRA=solicit + +[DHCPPrefixDelegation] +UplinkInterface=:self +SubnetId=0 +Announce=no</programlisting> + + <programlisting># /etc/systemd/network/55-dhcpv6-pd-downstream.network +[Match] +Name=enp2s0 + +[Network] +DHCPPrefixDelegation=yes +IPv6SendRA=yes + +# It is expected that the host is acting as a router. So, usually it is not +# necessary to receive Router Advertisement from other hosts in the downstream network. +IPv6AcceptRA=no + +[DHCPPrefixDelegation] +UplinkInterface=enp1s0 +SubnetId=1 +Announce=yes</programlisting> + + <para>This will enable DHCPv6-PD on the interface enp1s0 as an upstream interface where the + DHCPv6 client is running and enp2s0 as a downstream interface where the prefix is delegated to. + The delegated prefixes are distributed by IPv6 Router Advertisement on the downstream network. + </para> + </example> + + <example> + <title>IPv6 Prefix Delegation (DHCPv4 6RD)</title> + + <programlisting># /etc/systemd/network/55-dhcpv4-6rd-upstream.network +[Match] +Name=enp1s0 + +[Network] +DHCP=ipv4 + +# When DHCPv4-6RD is used, the upstream network does not support IPv6. +# Hence, it is not necessary to wait for Router Advertisement, which is enabled by default. +IPv6AcceptRA=no + +[DHCPv4] +Use6RD=yes</programlisting> + + <programlisting># /etc/systemd/network/55-dhcpv4-6rd-downstream.network +[Match] +Name=enp2s0 + +[Network] +DHCPPrefixDelegation=yes +IPv6SendRA=yes + +# It is expected that the host is acting as a router. So, usually it is not +# necessary to receive Router Advertisement from other hosts in the downstream network. +IPv6AcceptRA=no + +[DHCPPrefixDelegation] +UplinkInterface=enp1s0 +SubnetId=1 +Announce=yes</programlisting> + + <para>This will enable DHCPv4-6RD on the interface enp1s0 as an upstream interface where the + DHCPv4 client is running and enp2s0 as a downstream interface where the prefix is delegated to. + The delegated prefixes are distributed by IPv6 Router Advertisement on the downstream network. + </para> + </example> + + <example> + <title>A bridge with two enslaved links</title> + + <programlisting># /etc/systemd/network/25-bridge-static.netdev +[NetDev] +Name=bridge0 +Kind=bridge</programlisting> + + <programlisting># /etc/systemd/network/25-bridge-static.network +[Match] +Name=bridge0 + +[Network] +Address=192.168.0.15/24 +Gateway=192.168.0.1 +DNS=192.168.0.1</programlisting> + + <programlisting># /etc/systemd/network/25-bridge-slave-interface-1.network +[Match] +Name=enp2s0 + +[Network] +Bridge=bridge0</programlisting> + + <programlisting># /etc/systemd/network/25-bridge-slave-interface-2.network +[Match] +Name=wlp3s0 + +[Network] +Bridge=bridge0</programlisting> + + <para>This creates a bridge and attaches devices <literal>enp2s0</literal> and + <literal>wlp3s0</literal> to it. The bridge will have the specified static address + and network assigned, and a default route via the specified gateway will be + added. The specified DNS server will be added to the global list of DNS resolvers. + </para> + </example> + + <example> + <title>Bridge port with VLAN forwarding</title> + + <programlisting> +# /etc/systemd/network/25-bridge-slave-interface-1.network +[Match] +Name=enp2s0 + +[Network] +Bridge=bridge0 + +[BridgeVLAN] +VLAN=1-32 +PVID=42 +EgressUntagged=42 + +[BridgeVLAN] +VLAN=100-200 + +[BridgeVLAN] +EgressUntagged=300-400</programlisting> + + <para>This overrides the configuration specified in the previous example for the + interface <literal>enp2s0</literal>, and enables VLAN on that bridge port. VLAN IDs + 1-32, 42, 100-400 will be allowed. Packets tagged with VLAN IDs 42, 300-400 will be + untagged when they leave on this interface. Untagged packets which arrive on this + interface will be assigned VLAN ID 42.</para> + </example> + + <example> + <title>Various tunnels</title> + + <programlisting>/etc/systemd/network/25-tunnels.network +[Match] +Name=ens1 + +[Network] +Tunnel=ipip-tun +Tunnel=sit-tun +Tunnel=gre-tun +Tunnel=vti-tun + </programlisting> + + <programlisting>/etc/systemd/network/25-tunnel-ipip.netdev +[NetDev] +Name=ipip-tun +Kind=ipip + </programlisting> + + <programlisting>/etc/systemd/network/25-tunnel-sit.netdev +[NetDev] +Name=sit-tun +Kind=sit + </programlisting> + + <programlisting>/etc/systemd/network/25-tunnel-gre.netdev +[NetDev] +Name=gre-tun +Kind=gre + </programlisting> + + <programlisting>/etc/systemd/network/25-tunnel-vti.netdev +[NetDev] +Name=vti-tun +Kind=vti + </programlisting> + + <para>This will bring interface <literal>ens1</literal> up and create an IPIP tunnel, + a SIT tunnel, a GRE tunnel, and a VTI tunnel using it.</para> + </example> + + <example> + <title>A bond device</title> + + <programlisting># /etc/systemd/network/30-bond1.network +[Match] +Name=bond1 + +[Network] +DHCP=ipv6 +</programlisting> + + <programlisting># /etc/systemd/network/30-bond1.netdev +[NetDev] +Name=bond1 +Kind=bond +</programlisting> + + <programlisting># /etc/systemd/network/30-bond1-dev1.network +[Match] +MACAddress=52:54:00:e9:64:41 + +[Network] +Bond=bond1 +</programlisting> + + <programlisting># /etc/systemd/network/30-bond1-dev2.network +[Match] +MACAddress=52:54:00:e9:64:42 + +[Network] +Bond=bond1 +</programlisting> + + <para>This will create a bond device <literal>bond1</literal> and enslave the two + devices with MAC addresses 52:54:00:e9:64:41 and 52:54:00:e9:64:42 to it. IPv6 DHCP + will be used to acquire an address.</para> + </example> + + <example> + <title>Virtual Routing and Forwarding (VRF)</title> + <para>Add the <literal>bond1</literal> interface to the VRF master interface + <literal>vrf1</literal>. This will redirect routes generated on this interface to be + within the routing table defined during VRF creation. For kernels before 4.8 traffic + won't be redirected towards the VRFs routing table unless specific ip-rules are added. + </para> + <programlisting># /etc/systemd/network/25-vrf.network +[Match] +Name=bond1 + +[Network] +VRF=vrf1 +</programlisting> + </example> + + <example> + <title>MacVTap</title> + <para>This brings up a network interface <literal>macvtap-test</literal> + and attaches it to <literal>enp0s25</literal>.</para> + <programlisting># /usr/lib/systemd/network/25-macvtap.network +[Match] +Name=enp0s25 + +[Network] +MACVTAP=macvtap-test +</programlisting> + </example> + + <example> + <title>A Xfrm interface with physical underlying device.</title> + + <programlisting># /etc/systemd/network/27-xfrm.netdev +[NetDev] +Name=xfrm0 +Kind=xfrm + +[Xfrm] +InterfaceId=7</programlisting> + + <programlisting># /etc/systemd/network/27-eth0.network +[Match] +Name=eth0 + +[Network] +Xfrm=xfrm0</programlisting> + + <para>This creates a <literal>xfrm0</literal> interface and binds it to the <literal>eth0</literal> device. + This allows hardware based ipsec offloading to the <literal>eth0</literal> nic. + If offloading is not needed, xfrm interfaces can be assigned to the <literal>lo</literal> device. + </para> + </example> + </refsect1> + + <refsect1> + <title>See Also</title> + <para> + <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd-networkd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd.link</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd.netdev</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd-network-generator.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> + </para> + </refsect1> + +</refentry> |