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+<!doctype html public "-//W3C//DTD HTML 4.01 Transitional//EN"
+ "http://www.w3.org/TR/html4/loose.dtd">
+<html> <head>
+<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
+<title> Postfix manual - smtp(8) </title>
+</head> <body> <pre>
+SMTP(8) SMTP(8)
+
+<b>NAME</b>
+ smtp - Postfix SMTP+LMTP client
+
+<b>SYNOPSIS</b>
+ <b>smtp</b> [generic Postfix daemon options] [flags=DORX]
+
+<b>DESCRIPTION</b>
+ The Postfix SMTP+LMTP client implements the SMTP and LMTP mail delivery
+ protocols. It processes message delivery requests from the queue man-
+ ager. Each request specifies a queue file, a sender address, a domain
+ or host to deliver to, and recipient information. This program expects
+ to be run from the <a href="master.8.html"><b>master</b>(8)</a> process manager.
+
+ The SMTP+LMTP client updates the queue file and marks recipients as
+ finished, or it informs the queue manager that delivery should be tried
+ again at a later time. Delivery status reports are sent to the
+ <a href="bounce.8.html"><b>bounce</b>(8)</a>, <a href="defer.8.html"><b>defer</b>(8)</a> or <a href="trace.8.html"><b>trace</b>(8)</a> daemon as appropriate.
+
+ The SMTP+LMTP client looks up a list of mail exchanger addresses for
+ the destination host, sorts the list by preference, and connects to
+ each listed address until it finds a server that responds.
+
+ When a server is not reachable, or when mail delivery fails due to a
+ recoverable error condition, the SMTP+LMTP client will try to deliver
+ the mail to an alternate host.
+
+ After a successful mail transaction, a connection may be saved to the
+ <a href="scache.8.html"><b>scache</b>(8)</a> connection cache server, so that it may be used by any
+ SMTP+LMTP client for a subsequent transaction.
+
+ By default, connection caching is enabled temporarily for destinations
+ that have a high volume of mail in the <a href="QSHAPE_README.html#active_queue">active queue</a>. Connection caching
+ can be enabled permanently for specific destinations.
+
+<b>SMTP DESTINATION SYNTAX</b>
+ The Postfix SMTP+LMTP client supports multiple destinations separated
+ by comma or whitespace (Postfix 3.5 and later). SMTP destinations have
+ the following form:
+
+ <i>domainname</i>
+
+ <i>domainname</i>:<i>port</i>
+ Look up the mail exchangers for the specified domain, and con-
+ nect to the specified port (default: <b>smtp</b>).
+
+ [<i>hostname</i>]
+
+ [<i>hostname</i>]:<i>port</i>
+ Look up the address(es) of the specified host, and connect to
+ the specified port (default: <b>smtp</b>).
+
+ [<i>address</i>]
+
+ [<i>address</i>]:<i>port</i>
+ Connect to the host at the specified address, and connect to the
+ specified port (default: <b>smtp</b>). An IPv6 address must be format-
+ ted as [<b>ipv6</b>:<i>address</i>].
+
+<b>LMTP DESTINATION SYNTAX</b>
+ The Postfix SMTP+LMTP client supports multiple destinations separated
+ by comma or whitespace (Postfix 3.5 and later). LMTP destinations have
+ the following form:
+
+ <b>unix</b>:<i>pathname</i>
+ Connect to the local UNIX-domain server that is bound to the
+ specified <i>pathname</i>. If the process runs chrooted, an absolute
+ pathname is interpreted relative to the Postfix queue directory.
+
+ <b>inet</b>:<i>hostname</i>
+
+ <b>inet</b>:<i>hostname</i>:<i>port</i>
+
+ <b>inet</b>:[<i>address</i>]
+
+ <b>inet</b>:[<i>address</i>]:<i>port</i>
+ Connect to the specified TCP port on the specified local or
+ remote host. If no port is specified, connect to the port
+ defined as <b>lmtp</b> in <b>services</b>(4). If no such service is found,
+ the <b><a href="postconf.5.html#lmtp_tcp_port">lmtp_tcp_port</a></b> configuration parameter (default value of 24)
+ will be used. An IPv6 address must be formatted as
+ [<b>ipv6</b>:<i>address</i>].
+
+<b>SINGLE-RECIPIENT DELIVERY</b>
+ By default, the Postfix SMTP+LMTP client delivers mail to multiple
+ recipients per delivery request. This is undesirable when prepending a
+ <b>Delivered-to:</b> or <b>X-Original-To:</b> message header. To prevent Postfix from
+ sending multiple recipients per delivery request, specify
+
+ <b><a href="postconf.5.html#transport_destination_recipient_limit"><i>transport</i>_destination_recipient_limit</a> = 1</b>
+
+ in the Postfix <a href="postconf.5.html"><b>main.cf</b></a> file, where <i>transport</i> is the name in the first
+ column of the Postfix <a href="master.5.html"><b>master.cf</b></a> entry for this mail delivery service.
+
+<b>COMMAND ATTRIBUTE SYNTAX</b>
+ <b>flags=DORX</b> (optional)
+ Optional message processing flags.
+
+ <b>D</b> Prepend a "<b>Delivered-To:</b> <i>recipient</i>" message header with
+ the envelope recipient address. Note: for this to work,
+ the <b><a href="postconf.5.html#transport_destination_recipient_limit"><i>transport</i>_destination_recipient_limit</a></b> must be 1 (see
+ SINGLE-RECIPIENT DELIVERY above for details).
+
+ The <b>D</b> flag also enforces loop detection: if a message
+ already contains a <b>Delivered-To:</b> header with the same
+ recipient address, then the message is returned as unde-
+ liverable. The address comparison is case insensitive.
+
+ This feature is available as of Postfix 3.5.
+
+ <b>O</b> Prepend an "<b>X-Original-To:</b> <i>recipient</i>" message header with
+ the recipient address as given to Postfix. Note: for this
+ to work, the <b><a href="postconf.5.html#transport_destination_recipient_limit"><i>transport</i>_destination_recipient_limit</a></b> must
+ be 1 (see SINGLE-RECIPIENT DELIVERY above for details).
+
+ This feature is available as of Postfix 3.5.
+
+ <b>R</b> Prepend a "<b>Return-Path:</b> &lt;<i>sender</i>&gt;" message header with the
+ envelope sender address.
+
+ This feature is available as of Postfix 3.5.
+
+ <b>X</b> Indicates that the delivery is final. This flag affects
+ the status reported in "success" DSN (delivery status
+ notification) messages, and changes it from "relayed"
+ into "delivered".
+
+ This feature is available as of Postfix 3.5.
+
+<b>SECURITY</b>
+ The SMTP+LMTP client is moderately security-sensitive. It
+ talks to SMTP or LMTP servers and to DNS servers on the
+ network. The SMTP+LMTP client can be run chrooted at fixed
+ low privilege.
+
+<b>STANDARDS</b>
+ <a href="https://tools.ietf.org/html/rfc821">RFC 821</a> (SMTP protocol)
+ <a href="https://tools.ietf.org/html/rfc822">RFC 822</a> (ARPA Internet Text Messages)
+ <a href="https://tools.ietf.org/html/rfc1651">RFC 1651</a> (SMTP service extensions)
+ <a href="https://tools.ietf.org/html/rfc1652">RFC 1652</a> (8bit-MIME transport)
+ <a href="https://tools.ietf.org/html/rfc1870">RFC 1870</a> (Message Size Declaration)
+ <a href="https://tools.ietf.org/html/rfc2033">RFC 2033</a> (LMTP protocol)
+ <a href="https://tools.ietf.org/html/rfc2034">RFC 2034</a> (SMTP Enhanced Error Codes)
+ <a href="https://tools.ietf.org/html/rfc2045">RFC 2045</a> (MIME: Format of Internet Message Bodies)
+ <a href="https://tools.ietf.org/html/rfc2046">RFC 2046</a> (MIME: Media Types)
+ <a href="https://tools.ietf.org/html/rfc2554">RFC 2554</a> (AUTH command)
+ <a href="https://tools.ietf.org/html/rfc2821">RFC 2821</a> (SMTP protocol)
+ <a href="https://tools.ietf.org/html/rfc2920">RFC 2920</a> (SMTP Pipelining)
+ <a href="https://tools.ietf.org/html/rfc3207">RFC 3207</a> (STARTTLS command)
+ <a href="https://tools.ietf.org/html/rfc3461">RFC 3461</a> (SMTP DSN Extension)
+ <a href="https://tools.ietf.org/html/rfc3463">RFC 3463</a> (Enhanced Status Codes)
+ <a href="https://tools.ietf.org/html/rfc4954">RFC 4954</a> (AUTH command)
+ <a href="https://tools.ietf.org/html/rfc5321">RFC 5321</a> (SMTP protocol)
+ <a href="https://tools.ietf.org/html/rfc6531">RFC 6531</a> (Internationalized SMTP)
+ <a href="https://tools.ietf.org/html/rfc6533">RFC 6533</a> (Internationalized Delivery Status Notifications)
+ <a href="https://tools.ietf.org/html/rfc7672">RFC 7672</a> (SMTP security via opportunistic DANE TLS)
+
+<b>DIAGNOSTICS</b>
+ Problems and transactions are logged to <b>syslogd</b>(8) or <a href="postlogd.8.html"><b>postlogd</b>(8)</a>.
+ Corrupted message files are marked so that the queue manager can move
+ them to the <b>corrupt</b> queue for further inspection.
+
+ Depending on the setting of the <b><a href="postconf.5.html#notify_classes">notify_classes</a></b> parameter, the postmas-
+ ter is notified of bounces, protocol problems, and of other trouble.
+
+<b>BUGS</b>
+ SMTP and LMTP connection reuse for TLS (without closing the SMTP or
+ LMTP connection) is not supported before Postfix 3.4.
+
+ SMTP and LMTP connection reuse assumes that SASL credentials are valid
+ for all destinations that map onto the same IP address and TCP port.
+
+<b>CONFIGURATION PARAMETERS</b>
+ Before Postfix version 2.3, the LMTP client is a separate program that
+ implements only a subset of the functionality available with SMTP:
+ there is no support for TLS, and connections are cached in-process,
+ making it ineffective when the client is used for multiple domains.
+
+ Most smtp_<i>xxx</i> configuration parameters have an lmtp_<i>xxx</i> "mirror" param-
+ eter for the equivalent LMTP feature. This document describes only
+ those LMTP-related parameters that aren't simply "mirror" parameters.
+
+ Changes to <a href="postconf.5.html"><b>main.cf</b></a> are picked up automatically, as <a href="smtp.8.html"><b>smtp</b>(8)</a> processes
+ run for only a limited amount of time. Use the command "<b>postfix reload</b>"
+ to speed up a change.
+
+ The text below provides only a parameter summary. See <a href="postconf.5.html"><b>postconf</b>(5)</a> for
+ more details including examples.
+
+<b>COMPATIBILITY CONTROLS</b>
+ <b><a href="postconf.5.html#ignore_mx_lookup_error">ignore_mx_lookup_error</a> (no)</b>
+ Ignore DNS MX lookups that produce no response.
+
+ <b><a href="postconf.5.html#smtp_always_send_ehlo">smtp_always_send_ehlo</a> (yes)</b>
+ Always send EHLO at the start of an SMTP session.
+
+ <b><a href="postconf.5.html#smtp_never_send_ehlo">smtp_never_send_ehlo</a> (no)</b>
+ Never send EHLO at the start of an SMTP session.
+
+ <b><a href="postconf.5.html#smtp_defer_if_no_mx_address_found">smtp_defer_if_no_mx_address_found</a> (no)</b>
+ Defer mail delivery when no MX record resolves to an IP address.
+
+ <b><a href="postconf.5.html#smtp_line_length_limit">smtp_line_length_limit</a> (998)</b>
+ The maximal length of message header and body lines that Postfix
+ will send via SMTP.
+
+ <b><a href="postconf.5.html#smtp_pix_workaround_delay_time">smtp_pix_workaround_delay_time</a> (10s)</b>
+ How long the Postfix SMTP client pauses before sending
+ ".&lt;CR&gt;&lt;LF&gt;" in order to work around the PIX firewall
+ "&lt;CR&gt;&lt;LF&gt;.&lt;CR&gt;&lt;LF&gt;" bug.
+
+ <b><a href="postconf.5.html#smtp_pix_workaround_threshold_time">smtp_pix_workaround_threshold_time</a> (500s)</b>
+ How long a message must be queued before the Postfix SMTP client
+ turns on the PIX firewall "&lt;CR&gt;&lt;LF&gt;.&lt;CR&gt;&lt;LF&gt;" bug workaround for
+ delivery through firewalls with "smtp fixup" mode turned on.
+
+ <b><a href="postconf.5.html#smtp_pix_workarounds">smtp_pix_workarounds</a> (disable_esmtp, delay_dotcrlf)</b>
+ A list that specifies zero or more workarounds for CISCO PIX
+ firewall bugs.
+
+ <b><a href="postconf.5.html#smtp_pix_workaround_maps">smtp_pix_workaround_maps</a> (empty)</b>
+ Lookup tables, indexed by the remote SMTP server address, with
+ per-destination workarounds for CISCO PIX firewall bugs.
+
+ <b><a href="postconf.5.html#smtp_quote_rfc821_envelope">smtp_quote_rfc821_envelope</a> (yes)</b>
+ Quote addresses in Postfix SMTP client MAIL FROM and RCPT TO
+ commands as required by <a href="https://tools.ietf.org/html/rfc5321">RFC 5321</a>.
+
+ <b><a href="postconf.5.html#smtp_reply_filter">smtp_reply_filter</a> (empty)</b>
+ A mechanism to transform replies from remote SMTP servers one
+ line at a time.
+
+ <b><a href="postconf.5.html#smtp_skip_5xx_greeting">smtp_skip_5xx_greeting</a> (yes)</b>
+ Skip remote SMTP servers that greet with a 5XX status code.
+
+ <b><a href="postconf.5.html#smtp_skip_quit_response">smtp_skip_quit_response</a> (yes)</b>
+ Do not wait for the response to the SMTP QUIT command.
+
+ Available in Postfix version 2.0 and earlier:
+
+ <b><a href="postconf.5.html#smtp_skip_4xx_greeting">smtp_skip_4xx_greeting</a> (yes)</b>
+ Skip SMTP servers that greet with a 4XX status code (go away,
+ try again later).
+
+ Available in Postfix version 2.2 and later:
+
+ <b><a href="postconf.5.html#smtp_discard_ehlo_keyword_address_maps">smtp_discard_ehlo_keyword_address_maps</a> (empty)</b>
+ Lookup tables, indexed by the remote SMTP server address, with
+ case insensitive lists of EHLO keywords (pipelining, starttls,
+ auth, etc.) that the Postfix SMTP client will ignore in the EHLO
+ response from a remote SMTP server.
+
+ <b><a href="postconf.5.html#smtp_discard_ehlo_keywords">smtp_discard_ehlo_keywords</a> (empty)</b>
+ A case insensitive list of EHLO keywords (pipelining, starttls,
+ auth, etc.) that the Postfix SMTP client will ignore in the EHLO
+ response from a remote SMTP server.
+
+ <b><a href="postconf.5.html#smtp_generic_maps">smtp_generic_maps</a> (empty)</b>
+ Optional lookup tables that perform address rewriting in the
+ Postfix SMTP client, typically to transform a locally valid
+ address into a globally valid address when sending mail across
+ the Internet.
+
+ Available in Postfix version 2.2.9 and later:
+
+ <b><a href="postconf.5.html#smtp_cname_overrides_servername">smtp_cname_overrides_servername</a> (version dependent)</b>
+ When the remote SMTP servername is a DNS CNAME, replace the
+ servername with the result from CNAME expansion for the purpose
+ of logging, SASL password lookup, TLS policy decisions, or TLS
+ certificate verification.
+
+ Available in Postfix version 2.3 and later:
+
+ <b><a href="postconf.5.html#lmtp_discard_lhlo_keyword_address_maps">lmtp_discard_lhlo_keyword_address_maps</a> (empty)</b>
+ Lookup tables, indexed by the remote LMTP server address, with
+ case insensitive lists of LHLO keywords (pipelining, starttls,
+ auth, etc.) that the Postfix LMTP client will ignore in the LHLO
+ response from a remote LMTP server.
+
+ <b><a href="postconf.5.html#lmtp_discard_lhlo_keywords">lmtp_discard_lhlo_keywords</a> (empty)</b>
+ A case insensitive list of LHLO keywords (pipelining, starttls,
+ auth, etc.) that the Postfix LMTP client will ignore in the LHLO
+ response from a remote LMTP server.
+
+ Available in Postfix version 2.4.4 and later:
+
+ <b><a href="postconf.5.html#send_cyrus_sasl_authzid">send_cyrus_sasl_authzid</a> (no)</b>
+ When authenticating to a remote SMTP or LMTP server with the
+ default setting "no", send no SASL authoriZation ID (authzid);
+ send only the SASL authentiCation ID (authcid) plus the auth-
+ cid's password.
+
+ Available in Postfix version 2.5 and later:
+
+ <b><a href="postconf.5.html#smtp_header_checks">smtp_header_checks</a> (empty)</b>
+ Restricted <a href="header_checks.5.html"><b>header_checks</b>(5)</a> tables for the Postfix SMTP client.
+
+ <b><a href="postconf.5.html#smtp_mime_header_checks">smtp_mime_header_checks</a> (empty)</b>
+ Restricted <b><a href="postconf.5.html#mime_header_checks">mime_header_checks</a></b>(5) tables for the Postfix SMTP
+ client.
+
+ <b><a href="postconf.5.html#smtp_nested_header_checks">smtp_nested_header_checks</a> (empty)</b>
+ Restricted <b><a href="postconf.5.html#nested_header_checks">nested_header_checks</a></b>(5) tables for the Postfix SMTP
+ client.
+
+ <b><a href="postconf.5.html#smtp_body_checks">smtp_body_checks</a> (empty)</b>
+ Restricted <a href="header_checks.5.html"><b>body_checks</b>(5)</a> tables for the Postfix SMTP client.
+
+ Available in Postfix version 2.6 and later:
+
+ <b><a href="postconf.5.html#tcp_windowsize">tcp_windowsize</a> (0)</b>
+ An optional workaround for routers that break TCP window scal-
+ ing.
+
+ Available in Postfix version 2.8 and later:
+
+ <b><a href="postconf.5.html#smtp_dns_resolver_options">smtp_dns_resolver_options</a> (empty)</b>
+ DNS Resolver options for the Postfix SMTP client.
+
+ Available in Postfix version 2.9 - 3.6:
+
+ <b><a href="postconf.5.html#smtp_per_record_deadline">smtp_per_record_deadline</a> (no)</b>
+ Change the behavior of the smtp_*_timeout time limits, from a
+ time limit per read or write system call, to a time limit to
+ send or receive a complete record (an SMTP command line, SMTP
+ response line, SMTP message content line, or TLS protocol mes-
+ sage).
+
+ Available in Postfix version 2.9 and later:
+
+ <b><a href="postconf.5.html#smtp_send_dummy_mail_auth">smtp_send_dummy_mail_auth</a> (no)</b>
+ Whether or not to append the "AUTH=&lt;&gt;" option to the MAIL FROM
+ command in SASL-authenticated SMTP sessions.
+
+ Available in Postfix version 2.11 and later:
+
+ <b><a href="postconf.5.html#smtp_dns_support_level">smtp_dns_support_level</a> (empty)</b>
+ Level of DNS support in the Postfix SMTP client.
+
+ Available in Postfix version 3.0 and later:
+
+ <b><a href="postconf.5.html#smtp_delivery_status_filter">smtp_delivery_status_filter</a> ($<a href="postconf.5.html#default_delivery_status_filter">default_delivery_status_filter</a>)</b>
+ Optional filter for the <a href="smtp.8.html"><b>smtp</b>(8)</a> delivery agent to change the
+ delivery status code or explanatory text of successful or unsuc-
+ cessful deliveries.
+
+ <b><a href="postconf.5.html#smtp_dns_reply_filter">smtp_dns_reply_filter</a> (empty)</b>
+ Optional filter for Postfix SMTP client DNS lookup results.
+
+ Available in Postfix version 3.3 and later:
+
+ <b><a href="postconf.5.html#smtp_balance_inet_protocols">smtp_balance_inet_protocols</a> (yes)</b>
+ When a remote destination resolves to a combination of IPv4 and
+ IPv6 addresses, ensure that the Postfix SMTP client can try both
+ address types before it runs into the <a href="postconf.5.html#smtp_mx_address_limit">smtp_mx_address_limit</a>.
+
+ Available in Postfix 3.5 and later:
+
+ <b><a href="postconf.5.html#info_log_address_format">info_log_address_format</a> (external)</b>
+ The email address form that will be used in non-debug logging
+ (info, warning, etc.).
+
+ Available in Postfix 3.6 and later:
+
+ <b><a href="postconf.5.html#dnssec_probe">dnssec_probe</a> (ns:.)</b>
+ The DNS query type (default: "ns") and DNS query name (default:
+ ".") that Postfix may use to determine whether DNSSEC validation
+ is available.
+
+ <b><a href="postconf.5.html#known_tcp_ports">known_tcp_ports</a> (lmtp=24, smtp=25, smtps=submissions=465, submis-</b>
+ <b>sion=587)</b>
+ Optional setting that avoids lookups in the <b>services</b>(5) data-
+ base.
+
+ Available in Postfix version 3.7 and later:
+
+ <b><a href="postconf.5.html#smtp_per_request_deadline">smtp_per_request_deadline</a> (no)</b>
+ Change the behavior of the smtp_*_timeout time limits, from a
+ time limit per plaintext or TLS read or write call, to a com-
+ bined time limit for sending a complete SMTP request and for
+ receiving a complete SMTP response.
+
+ <b><a href="postconf.5.html#smtp_min_data_rate">smtp_min_data_rate</a> (500)</b>
+ The minimum plaintext data transfer rate in bytes/second for
+ DATA requests, when deadlines are enabled with
+ <a href="postconf.5.html#smtp_per_request_deadline">smtp_per_request_deadline</a>.
+
+ <b><a href="postconf.5.html#header_from_format">header_from_format</a> (standard)</b>
+ The format of the Postfix-generated <b>From:</b> header.
+
+<b>MIME PROCESSING CONTROLS</b>
+ Available in Postfix version 2.0 and later:
+
+ <b><a href="postconf.5.html#disable_mime_output_conversion">disable_mime_output_conversion</a> (no)</b>
+ Disable the conversion of 8BITMIME format to 7BIT format.
+
+ <b><a href="postconf.5.html#mime_boundary_length_limit">mime_boundary_length_limit</a> (2048)</b>
+ The maximal length of MIME multipart boundary strings.
+
+ <b><a href="postconf.5.html#mime_nesting_limit">mime_nesting_limit</a> (100)</b>
+ The maximal recursion level that the MIME processor will handle.
+
+<b>EXTERNAL CONTENT INSPECTION CONTROLS</b>
+ Available in Postfix version 2.1 and later:
+
+ <b><a href="postconf.5.html#smtp_send_xforward_command">smtp_send_xforward_command</a> (no)</b>
+ Send the non-standard XFORWARD command when the Postfix SMTP
+ server EHLO response announces XFORWARD support.
+
+<b>SASL AUTHENTICATION CONTROLS</b>
+ <b><a href="postconf.5.html#smtp_sasl_auth_enable">smtp_sasl_auth_enable</a> (no)</b>
+ Enable SASL authentication in the Postfix SMTP client.
+
+ <b><a href="postconf.5.html#smtp_sasl_password_maps">smtp_sasl_password_maps</a> (empty)</b>
+ Optional Postfix SMTP client lookup tables with one user-
+ name:password entry per sender, remote hostname or next-hop
+ domain.
+
+ <b><a href="postconf.5.html#smtp_sasl_security_options">smtp_sasl_security_options</a> (noplaintext, noanonymous)</b>
+ Postfix SMTP client SASL security options; as of Postfix 2.3 the
+ list of available features depends on the SASL client implemen-
+ tation that is selected with <b><a href="postconf.5.html#smtp_sasl_type">smtp_sasl_type</a></b>.
+
+ Available in Postfix version 2.2 and later:
+
+ <b><a href="postconf.5.html#smtp_sasl_mechanism_filter">smtp_sasl_mechanism_filter</a> (empty)</b>
+ If non-empty, a Postfix SMTP client filter for the remote SMTP
+ server's list of offered SASL mechanisms.
+
+ Available in Postfix version 2.3 and later:
+
+ <b><a href="postconf.5.html#smtp_sender_dependent_authentication">smtp_sender_dependent_authentication</a> (no)</b>
+ Enable sender-dependent authentication in the Postfix SMTP
+ client; this is available only with SASL authentication, and
+ disables SMTP connection caching to ensure that mail from dif-
+ ferent senders will use the appropriate credentials.
+
+ <b><a href="postconf.5.html#smtp_sasl_path">smtp_sasl_path</a> (empty)</b>
+ Implementation-specific information that the Postfix SMTP client
+ passes through to the SASL plug-in implementation that is
+ selected with <b><a href="postconf.5.html#smtp_sasl_type">smtp_sasl_type</a></b>.
+
+ <b><a href="postconf.5.html#smtp_sasl_type">smtp_sasl_type</a> (cyrus)</b>
+ The SASL plug-in type that the Postfix SMTP client should use
+ for authentication.
+
+ Available in Postfix version 2.5 and later:
+
+ <b><a href="postconf.5.html#smtp_sasl_auth_cache_name">smtp_sasl_auth_cache_name</a> (empty)</b>
+ An optional table to prevent repeated SASL authentication fail-
+ ures with the same remote SMTP server hostname, username and
+ password.
+
+ <b><a href="postconf.5.html#smtp_sasl_auth_cache_time">smtp_sasl_auth_cache_time</a> (90d)</b>
+ The maximal age of an <a href="postconf.5.html#smtp_sasl_auth_cache_name">smtp_sasl_auth_cache_name</a> entry before it
+ is removed.
+
+ <b><a href="postconf.5.html#smtp_sasl_auth_soft_bounce">smtp_sasl_auth_soft_bounce</a> (yes)</b>
+ When a remote SMTP server rejects a SASL authentication request
+ with a 535 reply code, defer mail delivery instead of returning
+ mail as undeliverable.
+
+ Available in Postfix version 2.9 and later:
+
+ <b><a href="postconf.5.html#smtp_send_dummy_mail_auth">smtp_send_dummy_mail_auth</a> (no)</b>
+ Whether or not to append the "AUTH=&lt;&gt;" option to the MAIL FROM
+ command in SASL-authenticated SMTP sessions.
+
+<b>STARTTLS SUPPORT CONTROLS</b>
+ Detailed information about STARTTLS configuration may be found in the
+ <a href="TLS_README.html">TLS_README</a> document.
+
+ <b><a href="postconf.5.html#smtp_tls_security_level">smtp_tls_security_level</a> (empty)</b>
+ The default SMTP TLS security level for the Postfix SMTP client;
+ when a non-empty value is specified, this overrides the obsolete
+ parameters <a href="postconf.5.html#smtp_use_tls">smtp_use_tls</a>, <a href="postconf.5.html#smtp_enforce_tls">smtp_enforce_tls</a>, and
+ <a href="postconf.5.html#smtp_tls_enforce_peername">smtp_tls_enforce_peername</a>.
+
+ <b><a href="postconf.5.html#smtp_sasl_tls_security_options">smtp_sasl_tls_security_options</a> ($<a href="postconf.5.html#smtp_sasl_security_options">smtp_sasl_security_options</a>)</b>
+ The SASL authentication security options that the Postfix SMTP
+ client uses for TLS encrypted SMTP sessions.
+
+ <b><a href="postconf.5.html#smtp_starttls_timeout">smtp_starttls_timeout</a> (300s)</b>
+ Time limit for Postfix SMTP client write and read operations
+ during TLS startup and shutdown handshake procedures.
+
+ <b><a href="postconf.5.html#smtp_tls_CAfile">smtp_tls_CAfile</a> (empty)</b>
+ A file containing CA certificates of root CAs trusted to sign
+ either remote SMTP server certificates or intermediate CA cer-
+ tificates.
+
+ <b><a href="postconf.5.html#smtp_tls_CApath">smtp_tls_CApath</a> (empty)</b>
+ Directory with PEM format Certification Authority certificates
+ that the Postfix SMTP client uses to verify a remote SMTP server
+ certificate.
+
+ <b><a href="postconf.5.html#smtp_tls_cert_file">smtp_tls_cert_file</a> (empty)</b>
+ File with the Postfix SMTP client RSA certificate in PEM format.
+
+ <b><a href="postconf.5.html#smtp_tls_mandatory_ciphers">smtp_tls_mandatory_ciphers</a> (medium)</b>
+ The minimum TLS cipher grade that the Postfix SMTP client will
+ use with mandatory TLS encryption.
+
+ <b><a href="postconf.5.html#smtp_tls_exclude_ciphers">smtp_tls_exclude_ciphers</a> (empty)</b>
+ List of ciphers or cipher types to exclude from the Postfix SMTP
+ client cipher list at all TLS security levels.
+
+ <b><a href="postconf.5.html#smtp_tls_mandatory_exclude_ciphers">smtp_tls_mandatory_exclude_ciphers</a> (empty)</b>
+ Additional list of ciphers or cipher types to exclude from the
+ Postfix SMTP client cipher list at mandatory TLS security lev-
+ els.
+
+ <b><a href="postconf.5.html#smtp_tls_dcert_file">smtp_tls_dcert_file</a> (empty)</b>
+ File with the Postfix SMTP client DSA certificate in PEM format.
+
+ <b><a href="postconf.5.html#smtp_tls_dkey_file">smtp_tls_dkey_file</a> ($<a href="postconf.5.html#smtp_tls_dcert_file">smtp_tls_dcert_file</a>)</b>
+ File with the Postfix SMTP client DSA private key in PEM format.
+
+ <b><a href="postconf.5.html#smtp_tls_key_file">smtp_tls_key_file</a> ($<a href="postconf.5.html#smtp_tls_cert_file">smtp_tls_cert_file</a>)</b>
+ File with the Postfix SMTP client RSA private key in PEM format.
+
+ <b><a href="postconf.5.html#smtp_tls_loglevel">smtp_tls_loglevel</a> (0)</b>
+ Enable additional Postfix SMTP client logging of TLS activity.
+
+ <b><a href="postconf.5.html#smtp_tls_note_starttls_offer">smtp_tls_note_starttls_offer</a> (no)</b>
+ Log the hostname of a remote SMTP server that offers STARTTLS,
+ when TLS is not already enabled for that server.
+
+ <b><a href="postconf.5.html#smtp_tls_policy_maps">smtp_tls_policy_maps</a> (empty)</b>
+ Optional lookup tables with the Postfix SMTP client TLS security
+ policy by next-hop destination; when a non-empty value is speci-
+ fied, this overrides the obsolete <a href="postconf.5.html#smtp_tls_per_site">smtp_tls_per_site</a> parameter.
+
+ <b><a href="postconf.5.html#smtp_tls_mandatory_protocols">smtp_tls_mandatory_protocols</a> (see 'postconf -d' output)</b>
+ TLS protocols that the Postfix SMTP client will use with manda-
+ tory TLS encryption.
+
+ <b><a href="postconf.5.html#smtp_tls_scert_verifydepth">smtp_tls_scert_verifydepth</a> (9)</b>
+ The verification depth for remote SMTP server certificates.
+
+ <b><a href="postconf.5.html#smtp_tls_secure_cert_match">smtp_tls_secure_cert_match</a> (nexthop, dot-nexthop)</b>
+ How the Postfix SMTP client verifies the server certificate
+ peername for the "secure" TLS security level.
+
+ <b><a href="postconf.5.html#smtp_tls_session_cache_database">smtp_tls_session_cache_database</a> (empty)</b>
+ Name of the file containing the optional Postfix SMTP client TLS
+ session cache.
+
+ <b><a href="postconf.5.html#smtp_tls_session_cache_timeout">smtp_tls_session_cache_timeout</a> (3600s)</b>
+ The expiration time of Postfix SMTP client TLS session cache
+ information.
+
+ <b><a href="postconf.5.html#smtp_tls_verify_cert_match">smtp_tls_verify_cert_match</a> (hostname)</b>
+ How the Postfix SMTP client verifies the server certificate
+ peername for the "verify" TLS security level.
+
+ <b><a href="postconf.5.html#tls_daemon_random_bytes">tls_daemon_random_bytes</a> (32)</b>
+ The number of pseudo-random bytes that an <a href="smtp.8.html"><b>smtp</b>(8)</a> or <a href="smtpd.8.html"><b>smtpd</b>(8)</a>
+ process requests from the <a href="tlsmgr.8.html"><b>tlsmgr</b>(8)</a> server in order to seed its
+ internal pseudo random number generator (PRNG).
+
+ <b><a href="postconf.5.html#tls_high_cipherlist">tls_high_cipherlist</a> (see 'postconf -d' output)</b>
+ The OpenSSL cipherlist for "high" grade ciphers.
+
+ <b><a href="postconf.5.html#tls_medium_cipherlist">tls_medium_cipherlist</a> (see 'postconf -d' output)</b>
+ The OpenSSL cipherlist for "medium" or higher grade ciphers.
+
+ <b><a href="postconf.5.html#tls_low_cipherlist">tls_low_cipherlist</a> (see 'postconf -d' output)</b>
+ The OpenSSL cipherlist for "low" or higher grade ciphers.
+
+ <b><a href="postconf.5.html#tls_export_cipherlist">tls_export_cipherlist</a> (see 'postconf -d' output)</b>
+ The OpenSSL cipherlist for "export" or higher grade ciphers.
+
+ <b><a href="postconf.5.html#tls_null_cipherlist">tls_null_cipherlist</a> (eNULL:!aNULL)</b>
+ The OpenSSL cipherlist for "NULL" grade ciphers that provide
+ authentication without encryption.
+
+ Available in Postfix version 2.4 and later:
+
+ <b><a href="postconf.5.html#smtp_sasl_tls_verified_security_options">smtp_sasl_tls_verified_security_options</a> ($<a href="postconf.5.html#smtp_sasl_tls_security_options">smtp_sasl_tls_secu</a>-</b>
+ <b><a href="postconf.5.html#smtp_sasl_tls_security_options">rity_options</a>)</b>
+ The SASL authentication security options that the Postfix SMTP
+ client uses for TLS encrypted SMTP sessions with a verified
+ server certificate.
+
+ Available in Postfix version 2.5 and later:
+
+ <b><a href="postconf.5.html#smtp_tls_fingerprint_cert_match">smtp_tls_fingerprint_cert_match</a> (empty)</b>
+ List of acceptable remote SMTP server certificate fingerprints
+ for the "fingerprint" TLS security level (<b><a href="postconf.5.html#smtp_tls_security_level">smtp_tls_secu</a>-</b>
+ <b><a href="postconf.5.html#smtp_tls_security_level">rity_level</a></b> = fingerprint).
+
+ <b><a href="postconf.5.html#smtp_tls_fingerprint_digest">smtp_tls_fingerprint_digest</a> (see 'postconf -d' output)</b>
+ The message digest algorithm used to construct remote SMTP
+ server certificate fingerprints.
+
+ Available in Postfix version 2.6 and later:
+
+ <b><a href="postconf.5.html#smtp_tls_protocols">smtp_tls_protocols</a> (see postconf -d output)</b>
+ TLS protocols that the Postfix SMTP client will use with oppor-
+ tunistic TLS encryption.
+
+ <b><a href="postconf.5.html#smtp_tls_ciphers">smtp_tls_ciphers</a> (medium)</b>
+ The minimum TLS cipher grade that the Postfix SMTP client will
+ use with opportunistic TLS encryption.
+
+ <b><a href="postconf.5.html#smtp_tls_eccert_file">smtp_tls_eccert_file</a> (empty)</b>
+ File with the Postfix SMTP client ECDSA certificate in PEM for-
+ mat.
+
+ <b><a href="postconf.5.html#smtp_tls_eckey_file">smtp_tls_eckey_file</a> ($<a href="postconf.5.html#smtp_tls_eccert_file">smtp_tls_eccert_file</a>)</b>
+ File with the Postfix SMTP client ECDSA private key in PEM for-
+ mat.
+
+ Available in Postfix version 2.7 and later:
+
+ <b><a href="postconf.5.html#smtp_tls_block_early_mail_reply">smtp_tls_block_early_mail_reply</a> (no)</b>
+ Try to detect a mail hijacking attack based on a TLS protocol
+ vulnerability (CVE-2009-3555), where an attacker prepends mali-
+ cious HELO, MAIL, RCPT, DATA commands to a Postfix SMTP client
+ TLS session.
+
+ Available in Postfix version 2.8 and later:
+
+ <b><a href="postconf.5.html#tls_disable_workarounds">tls_disable_workarounds</a> (see 'postconf -d' output)</b>
+ List or bit-mask of OpenSSL bug work-arounds to disable.
+
+ Available in Postfix version 2.11-3.1:
+
+ <b><a href="postconf.5.html#tls_dane_digest_agility">tls_dane_digest_agility</a> (on)</b>
+ Configure <a href="https://tools.ietf.org/html/rfc7671">RFC7671</a> DANE TLSA digest algorithm agility.
+
+ <b><a href="postconf.5.html#tls_dane_trust_anchor_digest_enable">tls_dane_trust_anchor_digest_enable</a> (yes)</b>
+ Enable support for <a href="https://tools.ietf.org/html/rfc6698">RFC 6698</a> (DANE TLSA) DNS records that contain
+ digests of trust-anchors with certificate usage "2".
+
+ Available in Postfix version 2.11 and later:
+
+ <b><a href="postconf.5.html#smtp_tls_trust_anchor_file">smtp_tls_trust_anchor_file</a> (empty)</b>
+ Zero or more PEM-format files with trust-anchor certificates
+ and/or public keys.
+
+ <b><a href="postconf.5.html#smtp_tls_force_insecure_host_tlsa_lookup">smtp_tls_force_insecure_host_tlsa_lookup</a> (no)</b>
+ Lookup the associated DANE TLSA RRset even when a hostname is
+ not an alias and its address records lie in an unsigned zone.
+
+ <b><a href="postconf.5.html#tlsmgr_service_name">tlsmgr_service_name</a> (tlsmgr)</b>
+ The name of the <a href="tlsmgr.8.html"><b>tlsmgr</b>(8)</a> service entry in <a href="master.5.html">master.cf</a>.
+
+ Available in Postfix version 3.0 and later:
+
+ <b><a href="postconf.5.html#smtp_tls_wrappermode">smtp_tls_wrappermode</a> (no)</b>
+ Request that the Postfix SMTP client connects using the legacy
+ SMTPS protocol instead of using the STARTTLS command.
+
+ Available in Postfix version 3.1 and later:
+
+ <b><a href="postconf.5.html#smtp_tls_dane_insecure_mx_policy">smtp_tls_dane_insecure_mx_policy</a> (see 'postconf -d' output)</b>
+ The TLS policy for MX hosts with "secure" TLSA records when the
+ nexthop destination security level is <b>dane</b>, but the MX record
+ was found via an "insecure" MX lookup.
+
+ Available in Postfix version 3.4 and later:
+
+ <b><a href="postconf.5.html#smtp_tls_connection_reuse">smtp_tls_connection_reuse</a> (no)</b>
+ Try to make multiple deliveries per TLS-encrypted connection.
+
+ <b><a href="postconf.5.html#smtp_tls_chain_files">smtp_tls_chain_files</a> (empty)</b>
+ List of one or more PEM files, each holding one or more private
+ keys directly followed by a corresponding certificate chain.
+
+ <b><a href="postconf.5.html#smtp_tls_servername">smtp_tls_servername</a> (empty)</b>
+ Optional name to send to the remote SMTP server in the TLS
+ Server Name Indication (SNI) extension.
+
+ Available in Postfix 3.5, 3.4.6, 3.3.5, 3.2.10, 3.1.13 and later:
+
+ <b><a href="postconf.5.html#tls_fast_shutdown_enable">tls_fast_shutdown_enable</a> (yes)</b>
+ A workaround for implementations that hang Postfix while shut-
+ ting down a TLS session, until Postfix times out.
+
+ Available in Postfix 3.9, 3.8.1, 3.7.6, 3.6.10, 3.5.20 and later:
+
+ <b><a href="postconf.5.html#tls_config_file">tls_config_file</a> (default)</b>
+ Optional configuration file with baseline OpenSSL settings.
+
+ <b><a href="postconf.5.html#tls_config_name">tls_config_name</a> (empty)</b>
+ The application name passed by Postfix to OpenSSL library ini-
+ tialization functions.
+
+<b>OBSOLETE STARTTLS CONTROLS</b>
+ The following configuration parameters exist for compatibility with
+ Postfix versions before 2.3. Support for these will be removed in a
+ future release.
+
+ <b><a href="postconf.5.html#smtp_use_tls">smtp_use_tls</a> (no)</b>
+ Opportunistic mode: use TLS when a remote SMTP server announces
+ STARTTLS support, otherwise send the mail in the clear.
+
+ <b><a href="postconf.5.html#smtp_enforce_tls">smtp_enforce_tls</a> (no)</b>
+ Enforcement mode: require that remote SMTP servers use TLS
+ encryption, and never send mail in the clear.
+
+ <b><a href="postconf.5.html#smtp_tls_enforce_peername">smtp_tls_enforce_peername</a> (yes)</b>
+ With mandatory TLS encryption, require that the remote SMTP
+ server hostname matches the information in the remote SMTP
+ server certificate.
+
+ <b><a href="postconf.5.html#smtp_tls_per_site">smtp_tls_per_site</a> (empty)</b>
+ Optional lookup tables with the Postfix SMTP client TLS usage
+ policy by next-hop destination and by remote SMTP server host-
+ name.
+
+ <b><a href="postconf.5.html#smtp_tls_cipherlist">smtp_tls_cipherlist</a> (empty)</b>
+ Obsolete Postfix &lt; 2.3 control for the Postfix SMTP client TLS
+ cipher list.
+
+<b>RESOURCE AND RATE CONTROLS</b>
+ <b><a href="postconf.5.html#smtp_connect_timeout">smtp_connect_timeout</a> (30s)</b>
+ The Postfix SMTP client time limit for completing a TCP connec-
+ tion, or zero (use the operating system built-in time limit).
+
+ <b><a href="postconf.5.html#smtp_helo_timeout">smtp_helo_timeout</a> (300s)</b>
+ The Postfix SMTP client time limit for sending the HELO or EHLO
+ command, and for receiving the initial remote SMTP server
+ response.
+
+ <b><a href="postconf.5.html#lmtp_lhlo_timeout">lmtp_lhlo_timeout</a> (300s)</b>
+ The Postfix LMTP client time limit for sending the LHLO command,
+ and for receiving the initial remote LMTP server response.
+
+ <b><a href="postconf.5.html#smtp_xforward_timeout">smtp_xforward_timeout</a> (300s)</b>
+ The Postfix SMTP client time limit for sending the XFORWARD com-
+ mand, and for receiving the remote SMTP server response.
+
+ <b><a href="postconf.5.html#smtp_mail_timeout">smtp_mail_timeout</a> (300s)</b>
+ The Postfix SMTP client time limit for sending the MAIL FROM
+ command, and for receiving the remote SMTP server response.
+
+ <b><a href="postconf.5.html#smtp_rcpt_timeout">smtp_rcpt_timeout</a> (300s)</b>
+ The Postfix SMTP client time limit for sending the SMTP RCPT TO
+ command, and for receiving the remote SMTP server response.
+
+ <b><a href="postconf.5.html#smtp_data_init_timeout">smtp_data_init_timeout</a> (120s)</b>
+ The Postfix SMTP client time limit for sending the SMTP DATA
+ command, and for receiving the remote SMTP server response.
+
+ <b><a href="postconf.5.html#smtp_data_xfer_timeout">smtp_data_xfer_timeout</a> (180s)</b>
+ The Postfix SMTP client time limit for sending the SMTP message
+ content.
+
+ <b><a href="postconf.5.html#smtp_data_done_timeout">smtp_data_done_timeout</a> (600s)</b>
+ The Postfix SMTP client time limit for sending the SMTP ".", and
+ for receiving the remote SMTP server response.
+
+ <b><a href="postconf.5.html#smtp_quit_timeout">smtp_quit_timeout</a> (300s)</b>
+ The Postfix SMTP client time limit for sending the QUIT command,
+ and for receiving the remote SMTP server response.
+
+ Available in Postfix version 2.1 and later:
+
+ <b><a href="postconf.5.html#smtp_mx_address_limit">smtp_mx_address_limit</a> (5)</b>
+ The maximal number of MX (mail exchanger) IP addresses that can
+ result from Postfix SMTP client mail exchanger lookups, or zero
+ (no limit).
+
+ <b><a href="postconf.5.html#smtp_mx_session_limit">smtp_mx_session_limit</a> (2)</b>
+ The maximal number of SMTP sessions per delivery request before
+ the Postfix SMTP client gives up or delivers to a fall-back
+ <a href="postconf.5.html#relayhost">relay host</a>, or zero (no limit).
+
+ <b><a href="postconf.5.html#smtp_rset_timeout">smtp_rset_timeout</a> (20s)</b>
+ The Postfix SMTP client time limit for sending the RSET command,
+ and for receiving the remote SMTP server response.
+
+ Available in Postfix version 2.2 and earlier:
+
+ <b><a href="postconf.5.html#lmtp_cache_connection">lmtp_cache_connection</a> (yes)</b>
+ Keep Postfix LMTP client connections open for up to $<a href="postconf.5.html#max_idle">max_idle</a>
+ seconds.
+
+ Available in Postfix version 2.2 and later:
+
+ <b><a href="postconf.5.html#smtp_connection_cache_destinations">smtp_connection_cache_destinations</a> (empty)</b>
+ Permanently enable SMTP connection caching for the specified
+ destinations.
+
+ <b><a href="postconf.5.html#smtp_connection_cache_on_demand">smtp_connection_cache_on_demand</a> (yes)</b>
+ Temporarily enable SMTP connection caching while a destination
+ has a high volume of mail in the <a href="QSHAPE_README.html#active_queue">active queue</a>.
+
+ <b><a href="postconf.5.html#smtp_connection_reuse_time_limit">smtp_connection_reuse_time_limit</a> (300s)</b>
+ The amount of time during which Postfix will use an SMTP connec-
+ tion repeatedly.
+
+ <b><a href="postconf.5.html#smtp_connection_cache_time_limit">smtp_connection_cache_time_limit</a> (2s)</b>
+ When SMTP connection caching is enabled, the amount of time that
+ an unused SMTP client socket is kept open before it is closed.
+
+ Available in Postfix version 2.3 and later:
+
+ <b><a href="postconf.5.html#connection_cache_protocol_timeout">connection_cache_protocol_timeout</a> (5s)</b>
+ Time limit for connection cache connect, send or receive opera-
+ tions.
+
+ Available in Postfix version 2.9 - 3.6:
+
+ <b><a href="postconf.5.html#smtp_per_record_deadline">smtp_per_record_deadline</a> (no)</b>
+ Change the behavior of the smtp_*_timeout time limits, from a
+ time limit per read or write system call, to a time limit to
+ send or receive a complete record (an SMTP command line, SMTP
+ response line, SMTP message content line, or TLS protocol mes-
+ sage).
+
+ Available in Postfix version 2.11 and later:
+
+ <b><a href="postconf.5.html#smtp_connection_reuse_count_limit">smtp_connection_reuse_count_limit</a> (0)</b>
+ When SMTP connection caching is enabled, the number of times
+ that an SMTP session may be reused before it is closed, or zero
+ (no limit).
+
+ Available in Postfix version 3.4 and later:
+
+ <b><a href="postconf.5.html#smtp_tls_connection_reuse">smtp_tls_connection_reuse</a> (no)</b>
+ Try to make multiple deliveries per TLS-encrypted connection.
+
+ Available in Postfix version 3.7 and later:
+
+ <b><a href="postconf.5.html#smtp_per_request_deadline">smtp_per_request_deadline</a> (no)</b>
+ Change the behavior of the smtp_*_timeout time limits, from a
+ time limit per plaintext or TLS read or write call, to a com-
+ bined time limit for sending a complete SMTP request and for
+ receiving a complete SMTP response.
+
+ <b><a href="postconf.5.html#smtp_min_data_rate">smtp_min_data_rate</a> (500)</b>
+ The minimum plaintext data transfer rate in bytes/second for
+ DATA requests, when deadlines are enabled with
+ <a href="postconf.5.html#smtp_per_request_deadline">smtp_per_request_deadline</a>.
+
+ Implemented in the <a href="qmgr.8.html">qmgr(8)</a> daemon:
+
+ <b><a href="postconf.5.html#transport_destination_concurrency_limit">transport_destination_concurrency_limit</a> ($<a href="postconf.5.html#default_destination_concurrency_limit">default_destination_concur</a>-</b>
+ <b><a href="postconf.5.html#default_destination_concurrency_limit">rency_limit</a>)</b>
+ A transport-specific override for the <a href="postconf.5.html#default_destination_concurrency_limit">default_destination_con</a>-
+ <a href="postconf.5.html#default_destination_concurrency_limit">currency_limit</a> parameter value, where <i>transport</i> is the <a href="master.5.html">master.cf</a>
+ name of the message delivery transport.
+
+ <b><a href="postconf.5.html#transport_destination_recipient_limit">transport_destination_recipient_limit</a> ($<a href="postconf.5.html#default_destination_recipient_limit">default_destination_recipi</a>-</b>
+ <b><a href="postconf.5.html#default_destination_recipient_limit">ent_limit</a>)</b>
+ A transport-specific override for the <a href="postconf.5.html#default_destination_recipient_limit">default_destination_recip</a>-
+ <a href="postconf.5.html#default_destination_recipient_limit">ient_limit</a> parameter value, where <i>transport</i> is the <a href="master.5.html">master.cf</a>
+ name of the message delivery transport.
+
+<b>SMTPUTF8 CONTROLS</b>
+ Preliminary SMTPUTF8 support is introduced with Postfix 3.0.
+
+ <b><a href="postconf.5.html#smtputf8_enable">smtputf8_enable</a> (yes)</b>
+ Enable preliminary SMTPUTF8 support for the protocols described
+ in <a href="https://tools.ietf.org/html/rfc6531">RFC 6531</a>..6533.
+
+ <b><a href="postconf.5.html#smtputf8_autodetect_classes">smtputf8_autodetect_classes</a> (sendmail, verify)</b>
+ Detect that a message requires SMTPUTF8 support for the speci-
+ fied mail origin classes.
+
+ Available in Postfix version 3.2 and later:
+
+ <b><a href="postconf.5.html#enable_idna2003_compatibility">enable_idna2003_compatibility</a> (no)</b>
+ Enable 'transitional' compatibility between IDNA2003 and
+ IDNA2008, when converting UTF-8 domain names to/from the ASCII
+ form that is used for DNS lookups.
+
+<b>TROUBLE SHOOTING CONTROLS</b>
+ <b><a href="postconf.5.html#debug_peer_level">debug_peer_level</a> (2)</b>
+ The increment in verbose logging level when a nexthop destina-
+ tion, remote client or server name or network address matches a
+ pattern given with the <a href="postconf.5.html#debug_peer_list">debug_peer_list</a> parameter.
+
+ <b><a href="postconf.5.html#debug_peer_list">debug_peer_list</a> (empty)</b>
+ Optional list of nexthop destination, remote client or server
+ name or network address patterns that, if matched, cause the
+ verbose logging level to increase by the amount specified in
+ $<a href="postconf.5.html#debug_peer_level">debug_peer_level</a>.
+
+ <b><a href="postconf.5.html#error_notice_recipient">error_notice_recipient</a> (postmaster)</b>
+ The recipient of postmaster notifications about mail delivery
+ problems that are caused by policy, resource, software or proto-
+ col errors.
+
+ <b><a href="postconf.5.html#internal_mail_filter_classes">internal_mail_filter_classes</a> (empty)</b>
+ What categories of Postfix-generated mail are subject to
+ before-queue content inspection by <a href="postconf.5.html#non_smtpd_milters">non_smtpd_milters</a>,
+ <a href="postconf.5.html#header_checks">header_checks</a> and <a href="postconf.5.html#body_checks">body_checks</a>.
+
+ <b><a href="postconf.5.html#notify_classes">notify_classes</a> (resource, software)</b>
+ The list of error classes that are reported to the postmaster.
+
+<b>MISCELLANEOUS CONTROLS</b>
+ <b><a href="postconf.5.html#best_mx_transport">best_mx_transport</a> (empty)</b>
+ Where the Postfix SMTP client should deliver mail when it
+ detects a "mail loops back to myself" error condition.
+
+ <b><a href="postconf.5.html#config_directory">config_directory</a> (see 'postconf -d' output)</b>
+ The default location of the Postfix <a href="postconf.5.html">main.cf</a> and <a href="master.5.html">master.cf</a> con-
+ figuration files.
+
+ <b><a href="postconf.5.html#daemon_timeout">daemon_timeout</a> (18000s)</b>
+ How much time a Postfix daemon process may take to handle a
+ request before it is terminated by a built-in watchdog timer.
+
+ <b><a href="postconf.5.html#delay_logging_resolution_limit">delay_logging_resolution_limit</a> (2)</b>
+ The maximal number of digits after the decimal point when log-
+ ging sub-second delay values.
+
+ <b><a href="postconf.5.html#disable_dns_lookups">disable_dns_lookups</a> (no)</b>
+ Disable DNS lookups in the Postfix SMTP and LMTP clients.
+
+ <b><a href="postconf.5.html#inet_interfaces">inet_interfaces</a> (all)</b>
+ The network interface addresses that this mail system receives
+ mail on.
+
+ <b><a href="postconf.5.html#inet_protocols">inet_protocols</a> (see 'postconf -d output')</b>
+ The Internet protocols Postfix will attempt to use when making
+ or accepting connections.
+
+ <b><a href="postconf.5.html#ipc_timeout">ipc_timeout</a> (3600s)</b>
+ The time limit for sending or receiving information over an
+ internal communication channel.
+
+ <b><a href="postconf.5.html#lmtp_assume_final">lmtp_assume_final</a> (no)</b>
+ When a remote LMTP server announces no DSN support, assume that
+ the server performs final delivery, and send "delivered" deliv-
+ ery status notifications instead of "relayed".
+
+ <b><a href="postconf.5.html#lmtp_tcp_port">lmtp_tcp_port</a> (24)</b>
+ The default TCP port that the Postfix LMTP client connects to.
+
+ <b><a href="postconf.5.html#max_idle">max_idle</a> (100s)</b>
+ The maximum amount of time that an idle Postfix daemon process
+ waits for an incoming connection before terminating voluntarily.
+
+ <b><a href="postconf.5.html#max_use">max_use</a> (100)</b>
+ The maximal number of incoming connections that a Postfix daemon
+ process will service before terminating voluntarily.
+
+ <b><a href="postconf.5.html#process_id">process_id</a> (read-only)</b>
+ The process ID of a Postfix command or daemon process.
+
+ <b><a href="postconf.5.html#process_name">process_name</a> (read-only)</b>
+ The process name of a Postfix command or daemon process.
+
+ <b><a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a> (empty)</b>
+ The network interface addresses that this mail system receives
+ mail on by way of a proxy or network address translation unit.
+
+ <b><a href="postconf.5.html#smtp_address_preference">smtp_address_preference</a> (any)</b>
+ The address type ("ipv6", "ipv4" or "any") that the Postfix SMTP
+ client will try first, when a destination has IPv6 and IPv4
+ addresses with equal MX preference.
+
+ <b><a href="postconf.5.html#smtp_bind_address">smtp_bind_address</a> (empty)</b>
+ An optional numerical network address that the Postfix SMTP
+ client should bind to when making an IPv4 connection.
+
+ <b><a href="postconf.5.html#smtp_bind_address6">smtp_bind_address6</a> (empty)</b>
+ An optional numerical network address that the Postfix SMTP
+ client should bind to when making an IPv6 connection.
+
+ <b><a href="postconf.5.html#smtp_helo_name">smtp_helo_name</a> ($<a href="postconf.5.html#myhostname">myhostname</a>)</b>
+ The hostname to send in the SMTP HELO or EHLO command.
+
+ <b><a href="postconf.5.html#lmtp_lhlo_name">lmtp_lhlo_name</a> ($<a href="postconf.5.html#myhostname">myhostname</a>)</b>
+ The hostname to send in the LMTP LHLO command.
+
+ <b><a href="postconf.5.html#smtp_host_lookup">smtp_host_lookup</a> (dns)</b>
+ What mechanisms the Postfix SMTP client uses to look up a host's
+ IP address.
+
+ <b><a href="postconf.5.html#smtp_randomize_addresses">smtp_randomize_addresses</a> (yes)</b>
+ Randomize the order of equal-preference MX host addresses.
+
+ <b><a href="postconf.5.html#syslog_facility">syslog_facility</a> (mail)</b>
+ The syslog facility of Postfix logging.
+
+ <b><a href="postconf.5.html#syslog_name">syslog_name</a> (see 'postconf -d' output)</b>
+ A prefix that is prepended to the process name in syslog
+ records, so that, for example, "smtpd" becomes "prefix/smtpd".
+
+ Available with Postfix 2.2 and earlier:
+
+ <b><a href="postconf.5.html#fallback_relay">fallback_relay</a> (empty)</b>
+ Optional list of relay hosts for SMTP destinations that can't be
+ found or that are unreachable.
+
+ Available with Postfix 2.3 and later:
+
+ <b><a href="postconf.5.html#smtp_fallback_relay">smtp_fallback_relay</a> ($<a href="postconf.5.html#fallback_relay">fallback_relay</a>)</b>
+ Optional list of relay hosts for SMTP destinations that can't be
+ found or that are unreachable.
+
+ Available with Postfix 3.0 and later:
+
+ <b><a href="postconf.5.html#smtp_address_verify_target">smtp_address_verify_target</a> (rcpt)</b>
+ In the context of email address verification, the SMTP protocol
+ stage that determines whether an email address is deliverable.
+
+ Available with Postfix 3.1 and later:
+
+ <b><a href="postconf.5.html#lmtp_fallback_relay">lmtp_fallback_relay</a> (empty)</b>
+ Optional list of relay hosts for LMTP destinations that can't be
+ found or that are unreachable.
+
+ Available with Postfix 3.2 and later:
+
+ <b><a href="postconf.5.html#smtp_tcp_port">smtp_tcp_port</a> (smtp)</b>
+ The default TCP port that the Postfix SMTP client connects to.
+
+ Available in Postfix 3.3 and later:
+
+ <b><a href="postconf.5.html#service_name">service_name</a> (read-only)</b>
+ The <a href="master.5.html">master.cf</a> service name of a Postfix daemon process.
+
+ Available in Postfix 3.7 and later:
+
+ <b><a href="postconf.5.html#smtp_bind_address_enforce">smtp_bind_address_enforce</a> (no)</b>
+ Defer delivery when the Postfix SMTP client cannot apply the
+ <a href="postconf.5.html#smtp_bind_address">smtp_bind_address</a> or <a href="postconf.5.html#smtp_bind_address6">smtp_bind_address6</a> setting.
+
+<b>SEE ALSO</b>
+ <a href="generic.5.html">generic(5)</a>, output address rewriting
+ <a href="header_checks.5.html">header_checks(5)</a>, message header content inspection
+ <a href="header_checks.5.html">body_checks(5)</a>, body parts content inspection
+ <a href="qmgr.8.html">qmgr(8)</a>, queue manager
+ <a href="bounce.8.html">bounce(8)</a>, delivery status reports
+ <a href="scache.8.html">scache(8)</a>, connection cache server
+ <a href="postconf.5.html">postconf(5)</a>, configuration parameters
+ <a href="master.5.html">master(5)</a>, generic daemon options
+ <a href="master.8.html">master(8)</a>, process manager
+ <a href="tlsmgr.8.html">tlsmgr(8)</a>, TLS session and PRNG management
+ <a href="postlogd.8.html">postlogd(8)</a>, Postfix logging
+ syslogd(8), system logging
+
+<b>README FILES</b>
+ <a href="SASL_README.html">SASL_README</a>, Postfix SASL howto
+ <a href="TLS_README.html">TLS_README</a>, Postfix STARTTLS howto
+
+<b>LICENSE</b>
+ The Secure Mailer license must be distributed with this software.
+
+<b>AUTHOR(S)</b>
+ Wietse Venema
+ IBM T.J. Watson Research
+ P.O. Box 704
+ Yorktown Heights, NY 10598, USA
+
+ Wietse Venema
+ Google, Inc.
+ 111 8th Avenue
+ New York, NY 10011, USA
+
+ Command pipelining in cooperation with:
+ Jon Ribbens
+ Oaktree Internet Solutions Ltd.,
+ Internet House,
+ Canal Basin,
+ Coventry,
+ CV1 4LY, United Kingdom.
+
+ SASL support originally by:
+ Till Franke
+ SuSE Rhein/Main AG
+ 65760 Eschborn, Germany
+
+ TLS support originally by:
+ Lutz Jaenicke
+ BTU Cottbus
+ Allgemeine Elektrotechnik
+ Universitaetsplatz 3-4
+ D-03044 Cottbus, Germany
+
+ Revised TLS and SMTP connection cache support by:
+ Victor Duchovni
+ Morgan Stanley
+
+ SMTP(8)
+</pre> </body> </html>