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diff --git a/man/systemd.network.xml b/man/systemd.network.xml new file mode 100644 index 0000000..ee464ff --- /dev/null +++ b/man/systemd.network.xml @@ -0,0 +1,2137 @@ +<?xml version='1.0'?> +<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" + "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> + +<!-- + SPDX-License-Identifier: LGPL-2.1+ +--> + +<refentry id="systemd.network" conditional='ENABLE_NETWORKD'> + + <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>Network setup is performed by + <citerefentry><refentrytitle>systemd-networkd</refentrytitle><manvolnum>8</manvolnum></citerefentry>. + </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 directory <filename>/usr/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 lexical order, regardless of the directories in which they live. + However, files with identical filenames replace each other. Files in <filename>/etc</filename> + have the highest priority, files in <filename>/run</filename> take precedence over files with + the same name in <filename>/usr/lib</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 parsed after the file itself is + 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 netdev file wherever located. (Of course, since + <filename>/run</filename> is temporary and <filename>/usr/lib</filename> is for vendors, it is + unlikely drop-ins should be used in either of those places.)</para> + + <para>Note that an interface without any static IPv6 addresses configured, and neither DHCPv6 + nor IPv6LL enabled, shall be considered to have no IPv6 support. IPv6 will be automatically + disabled for that interface by writing "1" to + <filename>/proc/sys/net/ipv6/conf/<replaceable>ifname</replaceable>/disable_ipv6</filename>. + </para> + </refsect1> + + <refsect1> + <title>[Match] Section Options</title> + + <para>The network file contains a <literal>[Match]</literal> + section, which determines if a given network file may be applied + to a given device; and a <literal>[Network]</literal> section + specifying how the device should be configured. The first (in + lexical order) of the network files that matches a given device + is applied, all later files are ignored, even if they match as + well.</para> + + <para>A network file is said to match a device if each of the + entries in the <literal>[Match]</literal> section matches, or if + the section is empty. The following keys are accepted:</para> + + <variablelist class='network-directives'> + <varlistentry> + <term><varname>MACAddress=</varname></term> + <listitem> + <para>A whitespace-separated list of hardware addresses. Use full colon-, hyphen- or dot-delimited hexadecimal. See the example below. + This option may appear more than one, in which case the lists are merged. If the empty string is assigned to this option, the list + of hardware addresses defined prior to this is reset.</para> + + <para>Example: + <programlisting>MACAddress=01:23:45:67:89:ab 00-11-22-33-44-55 AABB.CCDD.EEFF</programlisting></para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>Path=</varname></term> + <listitem> + <para>A whitespace-separated list of shell-style globs + matching the persistent path, as exposed by the udev + property <literal>ID_PATH</literal>. If the list is + prefixed with a "!", the test is inverted; i.e. it is + true when <literal>ID_PATH</literal> does not match any + item in the list.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>Driver=</varname></term> + <listitem> + <para>A whitespace-separated list of shell-style globs + matching the driver currently bound to the device, as + exposed by the udev property <literal>DRIVER</literal> + of its parent device, or if that is not set the driver + as exposed by <literal>ethtool -i</literal> of the + device itself. If the list is prefixed with a "!", the + test is inverted.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>Type=</varname></term> + <listitem> + <para>A whitespace-separated list of shell-style globs + matching the device type, as exposed by the udev property + <literal>DEVTYPE</literal>. If the list is prefixed with + a "!", the test is inverted.</para> + </listitem> + </varlistentry> + <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>. If the list is prefixed + with a "!", the test is inverted.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>Host=</varname></term> + <listitem> + <para>Matches against the hostname or machine ID of the + host. See <literal>ConditionHost=</literal> in + <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> + for details. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>Virtualization=</varname></term> + <listitem> + <para>Checks whether the system is executed in a virtualized + environment and optionally test whether it is a specific + implementation. See <literal>ConditionVirtualization=</literal> in + <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> + for details. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>KernelCommandLine=</varname></term> + <listitem> + <para>Checks whether a specific kernel command line option is + set (or if prefixed with the exclamation mark unset). See + <literal>ConditionKernelCommandLine=</literal> in + <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> + for details. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>KernelVersion=</varname></term> + <listitem> + <para>Checks whether the kernel version (as reported by <command>uname -r</command>) matches a certain + expression (or if prefixed with the exclamation mark does not match it). See + <literal>ConditionKernelVersion=</literal> in + <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> for + details. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>Architecture=</varname></term> + <listitem> + <para>Checks whether the system is running on a specific + architecture. See <literal>ConditionArchitecture=</literal> in + <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> + for details. + </para> + </listitem> + </varlistentry> + </variablelist> + + </refsect1> + + <refsect1> + <title>[Link] Section Options</title> + + <para> The <literal>[Link]</literal> 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.</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.</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.</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>RequiredForOnline=</varname></term> + <listitem> + <para>Takes a boolean. When <literal>yes</literal>, the network is deemed + required when determining whether the system is online when running + <literal>systemd-networkd-wait-online</literal>. + When <literal>no</literal>, the network is ignored when checking for + online state. Defaults to <literal>yes</literal>.</para> + <para>The network will be brought up normally in all cases, 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 <literal>systemd-networkd-wait-online</literal> + if <literal>RequiredForOnline=no</literal>.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[Network] Section Options</title> + + <para>The <literal>[Network]</literal> 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 + Advertisement, if that is enabled, regardless of this parameter. + By enabling DHCPv6 support explicitly, the DHCPv6 client will + be started regardless of the presence of routers on the link, + or what flags the routers pass. See + <literal>IPv6AcceptRA=</literal>.</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 <literal>[DHCP]</literal> section 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 start. Defaults + to <literal>no</literal>. Further settings for the DHCP + server may be set in the <literal>[DHCPServer]</literal> + section described below.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>LinkLocalAddressing=</varname></term> + <listitem> + <para>Enables link-local address autoconfiguration. Accepts + <literal>yes</literal>, <literal>no</literal>, + <literal>ipv4</literal>, or <literal>ipv6</literal>. Defaults to + <literal>ipv6</literal>.</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>IPv6Token=</varname></term> + <listitem> + <para>An IPv6 address with the top 64 bits unset. When set, indicates the + 64-bit interface part of SLAAC IPv6 addresses for this link. Note that + the token is only ever used for SLAAC, and not for DHCPv6 addresses, even + in the case DHCP is requested by router advertisement. By default, the + token is autogenerated.</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 false or + <literal>opportunistic</literal>. When set to <literal>opportunistic</literal>, enables + <ulink + url="https://tools.ietf.org/html/rfc7858">DNS-over-TLS</ulink> + support on the link. 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 + false. 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 + false. 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 host name, 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> + </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 0.0.0.0 (for IPv4) or + [::] (for IPv6), a new address range of the requested size + is automatically allocated from a system-wide pool of + unused ranges. 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 fc00::/7 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 Gateway 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. 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 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 host names (host names containing no dots) to + become fully qualified domain names (FQDNs). If a single-label host name 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 host names + 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. 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://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt">ip-sysctl.txt</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 a boolean argument. Implies + <varname>IPForward=ipv4</varname>. Defaults to + <literal>no</literal>.</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, independently of the local forwarding state. + If unset, the kernel's default is used, and RAs are accepted only when local forwarding + is disabled for that interface. 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.</para> + + <para>Further settings for the IPv6 RA support may be configured in the + <literal>[IPv6AcceptRA]</literal> section, see below.</para> + + <para>Also see <ulink + url="https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt">ip-sysctl.txt</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> + </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>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 + <option>IPv6ProxyNDPAddress=</option> entries to the kernel's IPv6 neighbor proxy table. + This option implies <option>IPv6ProxyNDP=yes</option> but has no effect if + <option>IPv6ProxyNDP</option> has been set to false. When unset, the kernel's default will be used. + </para></listitem> + </varlistentry> + <varlistentry> + <term><varname>IPv6PrefixDelegation=</varname></term> + <listitem><para>Whether to enable or disable Router Advertisement sending on a link. + Allowed values are <literal>static</literal> which distributes prefixes as defined in + the <literal>[IPv6PrefixDelegation]</literal> and any <literal>[IPv6Prefix]</literal> + sections, <literal>dhcpv6</literal> which requests prefixes using a DHCPv6 client + configured for another link and any values configured in the + <literal>[IPv6PrefixDelegation]</literal> section while ignoring all static prefix + configuration sections, <literal>yes</literal> which uses both static configuration + and DHCPv6, and <literal>false</literal> which turns off IPv6 prefix delegation + altogether. Defaults to <literal>false</literal>. See the + <literal>[IPv6PrefixDelegation]</literal> and the <literal>[IPv6Prefix]</literal> + sections for more configuration options. + </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>Bridge=</varname></term> + <listitem> + <para>The name of the bridge to add the link to. See + <citerefentry><refentrytitle>systemd.netdev</refentrytitle><manvolnum>5</manvolnum></citerefentry>. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>Bond=</varname></term> + <listitem> + <para>The name of the bond to add the link to. See + <citerefentry><refentrytitle>systemd.netdev</refentrytitle><manvolnum>5</manvolnum></citerefentry>. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>VRF=</varname></term> + <listitem> + <para>The name of the VRF to add the link to. See + <citerefentry><refentrytitle>systemd.netdev</refentrytitle><manvolnum>5</manvolnum></citerefentry>. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>VLAN=</varname></term> + <listitem> + <para>The name of a VLAN to create 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>IPVLAN=</varname></term> + <listitem> + <para>The name of a IPVLAN to create 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>MACVLAN=</varname></term> + <listitem> + <para>The name of a MACVLAN to create 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>VXLAN=</varname></term> + <listitem> + <para>The name of a VXLAN to create 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>Tunnel=</varname></term> + <listitem> + <para>The name of a Tunnel to create 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. + </para> + </listitem> + </varlistentry> + </variablelist> + + </refsect1> + + <refsect1> + <title>[Address] Section Options</title> + + <para>An <literal>[Address]</literal> section accepts the + following keys. Specify several <literal>[Address]</literal> + sections to configure several addresses.</para> + + <variablelist class='network-directives'> + <varlistentry> + <term><varname>Address=</varname></term> + <listitem> + <para>As in the <literal>[Network]</literal> section. This + key is mandatory.</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 <literal>Address</literal> + key.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>Broadcast=</varname></term> + <listitem> + <para>The broadcast address, which must be in the format + described in + <citerefentry project='man-pages'><refentrytitle>inet_pton</refentrytitle><manvolnum>3</manvolnum></citerefentry>. + This key only applies to IPv4 addresses. If it is not + given, it is derived from the <literal>Address</literal> + key.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>Label=</varname></term> + <listitem> + <para>An address label.</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> or <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 PreferredLifetime=0 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>, + <literal>link</literal> or <literal>host</literal> or an unsigned integer ranges 0 to 255. + Defaults to <literal>global</literal>.</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 a boolean. Do not perform Duplicate Address Detection + <ulink url="https://tools.ietf.org/html/rfc4862">RFC 4862</ulink> when adding this address. + Supported only on IPv6. Defaults to false.</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 to use privacy + extensions in a manually configured network, just like if stateless auto-configuration + was active. Defaults to false. </para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>PrefixRoute=</varname></term> + <listitem> + <para>Takes a boolean. When adding or modifying an IPv6 address, the userspace + application needs a way to suppress adding a prefix route. This is for example relevant + together with IFA_F_MANAGERTEMPADDR, where userspace creates autoconf generated addresses, + but depending on on-link, no route for the prefix should be added. Defaults to false.</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 then to do the required join. By extending ip address 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> + </variablelist> + </refsect1> + + <refsect1> + <title>[Neighbor] Section Options</title> + <para>A <literal>[Neighbor]</literal> 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 <literal>[Neighbor]</literal> 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>MACAddress=</varname></term> + <listitem> + <para>The hardware address of the neighbor.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[IPv6AddressLabel] Section Options</title> + + <para>An <literal>[IPv6AddressLabel]</literal> section accepts the + following keys. Specify several <literal>[IPv6AddressLabel]</literal> + 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) ranges 0 to 4294967294. + 0xffffffff is reserved. This key 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 key is mandatory. </para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[RoutingPolicyRule] Section Options</title> + + <para>An <literal>[RoutingPolicyRule]</literal> section accepts the + following keys. Specify several <literal>[RoutingPolicyRule]</literal> + sections to configure several rules.</para> + + <variablelist class='network-directives'> + <varlistentry> + <term><varname>TypeOfService=</varname></term> + <listitem> + <para>Specifies the type of service to match a number between 0 to 255.</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 between 1 and 4294967295).</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>Table=</varname></term> + <listitem> + <para>Specifies the routing table identifier to lookup if the rule + selector matches. The table identifier for a route (a number between 1 and 4294967295).</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>Priority=</varname></term> + <listitem> + <para>Specifies the priority of this rule. <varname>Priority=</varname> is an unsigned + integer. Higher number means lower priority, and rules get processed in order of increasing number.</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 wheather the rule to be inverted. Defaults to false.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[Route] Section Options</title> + <para>The <literal>[Route]</literal> section accepts the + following keys. Specify several <literal>[Route]</literal> + sections to configure several routes.</para> + + <variablelist class='network-directives'> + <varlistentry> + <term><varname>Gateway=</varname></term> + <listitem> + <para>As in the <literal>[Network]</literal> section.</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., the kernel does + not need to check if the gateway is 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 (an unsigned integer).</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">RFC4191</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 route, which can be <literal>global</literal>, + <literal>link</literal> or <literal>host</literal>. Defaults to + <literal>global</literal>.</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=<replaceable>num</replaceable></varname></term> + <listitem> + <para>The table identifier for the route (a number between 1 and 4294967295, or 0 to unset). + The table can be retrieved using <command>ip route show table <replaceable>num</replaceable></command>. + </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> and <literal>static</literal>. Defaults to + <literal>static</literal>. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>Type=</varname></term> + <listitem> + <para>Specifies the type for the route. 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 data bytes + will be sent during the initial burst of data. Takes a size in bytes between 1 and 4294967295 (2^32 - 1). The usual + suffixes K, M, G are supported and are understood to the base of 1024. When unset, the kernel's default 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 initally 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 size in bytes between 1 and 4294967295 (2^32 - 1). The usual suffixes K, M, G are supported + and are understood to the base of 1024. 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>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> + <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> + </variablelist> + </refsect1> + + <refsect1> + <title>[DHCP] Section Options</title> + <para>The <literal>[DHCP]</literal> section configures the + DHCPv4 and DHCP6 client, if it is enabled with the + <varname>DHCP=</varname> setting described above:</para> + + <variablelist class='network-directives'> + <varlistentry> + <term><varname>UseDNS=</varname></term> + <listitem> + <para>When true (the default), the DNS servers received + from the DHCP server will be used and take precedence over + any statically configured ones.</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>UseNTP=</varname></term> + <listitem> + <para>When true (the default), the NTP servers received + from the DHCP server will be used by systemd-timesyncd + and take precedence over any statically configured ones.</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> + </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 <literal>random</literal> + (see <citerefentry + project='man-pages'><refentrytitle>systemd.link</refentrytitle><manvolnum>5</manvolnum></citerefentry>).</para> + + <para>Note that this configuration will overwrite others. + In concrete, the following variables will be ignored: + <varname>SendHostname=</varname>, <varname>ClientIdentifier=</varname>, + <varname>UseRoutes=</varname>, <varname>SendHostname=</varname>, + <varname>UseMTU=</varname>, <varname>VendorClassIdentifier=</varname>, + <varname>UseTimezone=</varname>.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><varname>SendHostname=</varname></term> + <listitem> + <para>When true (the default), the machine's hostname will be sent to the DHCP server. + Note that the machine's 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 is set to true.</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>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>UseDomains=</varname></term> + <listitem> + <para>Takes a boolean, or the special value <literal>route</literal>. When true, the domain name + received from the DHCP server will be used as DNS search domain over this link, similar to the effect of + the <option>Domains=</option> setting. If set to <literal>route</literal>, the domain name received from + the DHCP server will be used for routing DNS queries only, but not for searching, similar 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 host names, 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 "global", "link" or "host", 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 "host". Otherwise if the gateway is null (a direct route), a + "link" scope will be used. For anything else, scope defaults to "global".</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 <literal>no</literal>.</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>CriticalConnection=</varname></term> + <listitem> + <para>When true, the connection will never be torn down + even if the DHCP lease expires. This is contrary to the + DHCP specification, but may be the best choice if, say, + the root filesystem relies on this connection. Defaults to + false.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>ClientIdentifier=</varname></term> + <listitem> + <para>The DHCPv4 client identifier to use. Takes one of <literal>mac</literal>, <literal>duid</literal> or <literal>duid-only</literal>. + If set to <literal>mac</literal>, the MAC address of the link is used. + If set to <literal>duid</literal>, an RFC4361-compliant Client ID, which is the combination of IAID and DUID (see below), is used. + If set to <literal>duid-only</literal>, only DUID is used, this may not be RFC compliant, but some setups may require to use this. + Defaults to <literal>duid</literal>.</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>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>RouteMetric=</varname></term> + <listitem> + <para>Set the routing metric for routes specified by the + DHCP server.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>RouteTable=<replaceable>num</replaceable></varname></term> + <listitem> + <para>The table identifier for DHCP routes (a number between 1 and 4294967295, or 0 to unset). + The table can be retrieved using <command>ip route show table <replaceable>num</replaceable></command>. + </para> + <para>When used in combination with <varname>VRF=</varname> the + VRF's routing table is used unless this parameter is specified. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>ListenPort=</varname></term> + <listitem> + <para>Allow setting custom port for the DHCP client to listen on.</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 enabled by both + the DHCPv6 client and the DHCPv6 server, the two-message exchange is used, rather than the default + four-method exchange (solicit, advertise, request, and reply). The two-message exchange provides + faster client configuration and is beneficial in environments in which networks are under a heavy load. + See <ulink url="https://tools.ietf.org/html/rfc3315#section-17.2.1">RFC 3315</ulink> for details. + Defaults to true.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><varname>ForceDHCPv6PDOtherInformation=</varname></term> + <listitem> + <para>Takes a boolean that enforces DHCPv6 stateful mode when the 'Other information' bit is set in + Router Advertisement messages. By default setting only the 'O' bit in Router Advertisements + makes DHCPv6 request network information in a stateless manner using a two-message Information + Request and Information Reply message exchange. + <ulink url="https://tools.ietf.org/html/rfc7084">RFC 7084</ulink>, requirement WPD-4, updates + this behavior for a Customer Edge router so that stateful DHCPv6 Prefix Delegation is also + requested when only the 'O' bit is set in Router Advertisements. This option enables such a CE + behavior as it is impossible to automatically distinguish the intention of the 'O' bit otherwise. + By default this option is set to 'false', enable it if no prefixes are delegated when the device + should be acting as a CE router.</para> + </listitem> + </varlistentry> + + </variablelist> + </refsect1> + + <refsect1> + <title>[IPv6AcceptRA] Section Options</title> + <para>The <literal>[IPv6AcceptRA]</literal> 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>UseDNS=</varname></term> + <listitem> + <para>When true (the default), the DNS servers received in the Router Advertisement will be used and take + precedence over any statically configured ones.</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, similar 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, similar 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 host names, 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 + (a number between 1 and 4294967295, or 0 to unset). + The table can be retrieved using <command>ip route show table <replaceable>num</replaceable></command>. + </para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>[DHCPServer] Section Options</title> + <para>The <literal>[DHCPServer]</literal> 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>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>EmitDNS=</varname></term> + <term><varname>DNS=</varname></term> + + <listitem><para>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. 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 or NTP server information at a + later point. DNS server propagation does not take + <filename>/etc/resolv.conf</filename> into account. 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></listitem> + </varlistentry> + + <varlistentry> + <term><varname>EmitNTP=</varname></term> + <term><varname>NTP=</varname></term> + + <listitem><para>Similar to the <varname>EmitDNS=</varname> and + <varname>DNS=</varname> settings described above, these + settings configure whether and what NTP server information + 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> + + <listitem><para>Similar to the <varname>EmitDNS=</varname> + setting described above, this setting configures whether the + DHCP lease should contain the router option. The same syntax, + propagation semantics and defaults apply as for + <varname>EmitDNS=</varname>.</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> + + </variablelist> + </refsect1> + + <refsect1> + <title>[IPv6PrefixDelegation] Section Options</title> + <para>The <literal>[IPv6PrefixDelegation]</literal> section contains + settings for sending IPv6 Router Advertisements and whether to act as + a router, if enabled via the <varname>IPv6PrefixDelegation=</varname> + option described above. IPv6 network prefixes are defined with one or + more <literal>[IPv6Prefix]</literal> 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. If set, + this host also announces itself in Router Advertisements as an IPv6 + router for the network link. When unset, the host is not acting as a router.</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>EmitDNS=</varname></term> + <term><varname>DNS=</varname></term> + + <listitem><para><varname>DNS=</varname> specifies a list of recursive + DNS server IPv6 addresses that distributed via Router Advertisement + messages when <varname>EmitDNS=</varname> is true. If <varname>DNS= + </varname> is empty, DNS servers are read from the + <literal>[Network]</literal> section. If the + <literal>[Network]</literal> section does not contain any DNS servers + either, DNS servers from the uplink with the highest priority default + route are 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 + <literal>[Network]</literal> section. If the <literal>[Network]</literal> + section does not contain any DNS search domains either, DNS search + domains from the uplink with the highest priority default route are + 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>.</para></listitem> + </varlistentry> + + </variablelist> + </refsect1> + + <refsect1> + <title>[IPv6Prefix] Section Options</title> + <para>One or more <literal>[IPv6Prefix]</literal> 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 + <literal>[IPv6Prefix]</literal> 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 604800 + seconds (one week) and <varname>ValidLifetimeSec=</varname> defaults + to 2592000 seconds (30 days).</para></listitem> + </varlistentry> + + </variablelist> + </refsect1> + + <refsect1> + <title>[Bridge] Section Options</title> + <para>The <literal>[Bridge]</literal> 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>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>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, and 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>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>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 <literal>[BridgeFDB]</literal> section manages the + forwarding database table of a port and accepts the following + keys. Specify several <literal>[BridgeFDB]</literal> sections to + configure several static MAC table entries.</para> + + <variablelist class='network-directives'> + <varlistentry> + <term><varname>MACAddress=</varname></term> + <listitem> + <para>As in the <literal>[Network]</literal> section. This + key is mandatory.</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> + </variablelist> + </refsect1> + + <refsect1> + <title>[CAN] Section Options</title> + <para>The <literal>[CAN]</literal> 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.</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>).</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> + </variablelist> + </refsect1> + + <refsect1> + <title>[BridgeVLAN] Section Options</title> + <para>The <literal>[BridgeVLAN]</literal> section manages the VLAN ID configuration of a bridge port and accepts + the following keys. Specify several <literal>[BridgeVLAN]</literal> sections to configure several VLAN entries. + The <varname>VLANFiltering=</varname> option has to be enabled, see <literal>[Bridge]</literal> 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. VLAN IDs are valid + from 1 to 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>A bridge with two enslaved links</title> + + <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></title> + + <programlisting> +# /etc/systemd/network/20-bridge-slave-interface-vlan.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> + </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-resolved.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> + </para> + </refsect1> + +</refentry> |