Adding upstream version 3.7.10.upstream/3.7.10

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 975 insertions, 0 deletions

diff --git a/man/man8/smtp.8 b/man/man8/smtp.8
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+.TH SMTP 8 
+.ad
+.fi
+.SH NAME
+smtp
+\-
+Postfix SMTP+LMTP client
+.SH "SYNOPSIS"
+.na
+.nf
+\fBsmtp\fR [generic Postfix daemon options] [flags=DORX]
+.SH DESCRIPTION
+.ad
+.fi
+The Postfix SMTP+LMTP client implements the SMTP and LMTP mail
+delivery protocols. It processes message delivery requests from
+the queue manager. 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 \fBmaster\fR(8) 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 \fBbounce\fR(8), \fBdefer\fR(8) or \fBtrace\fR(8) 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 \fBscache\fR(8) 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 active
+queue. Connection caching can be enabled permanently for
+specific destinations.
+.SH "SMTP DESTINATION SYNTAX"
+.na
+.nf
+.ad
+.fi
+The Postfix SMTP+LMTP client supports multiple destinations
+separated by comma or whitespace (Postfix 3.5 and later).
+SMTP destinations have the following form:
+.IP \fIdomainname\fR
+.IP \fIdomainname\fR:\fIport\fR
+Look up the mail exchangers for the specified domain, and
+connect to the specified port (default: \fBsmtp\fR).
+.IP [\fIhostname\fR]
+.IP [\fIhostname\fR]:\fIport\fR
+Look up the address(es) of the specified host, and connect to
+the specified port (default: \fBsmtp\fR).
+.IP [\fIaddress\fR]
+.IP [\fIaddress\fR]:\fIport\fR
+Connect to the host at the specified address, and connect
+to the specified port (default: \fBsmtp\fR). An IPv6 address
+must be formatted as [\fBipv6\fR:\fIaddress\fR].
+.SH "LMTP DESTINATION SYNTAX"
+.na
+.nf
+.ad
+.fi
+The Postfix SMTP+LMTP client supports multiple destinations
+separated by comma or whitespace (Postfix 3.5 and later).
+LMTP destinations have the following form:
+.IP \fBunix\fR:\fIpathname\fR
+Connect to the local UNIX\-domain server that is bound to the specified
+\fIpathname\fR. If the process runs chrooted, an absolute pathname
+is interpreted relative to the Postfix queue directory.
+.IP \fBinet\fR:\fIhostname\fR
+.IP \fBinet\fR:\fIhostname\fR:\fIport\fR
+.IP \fBinet\fR:[\fIaddress\fR]
+.IP \fBinet\fR:[\fIaddress\fR]:\fIport\fR
+Connect to the specified TCP port on the specified local or
+remote host. If no port is specified, connect to the port defined as
+\fBlmtp\fR in \fBservices\fR(4).
+If no such service is found, the \fBlmtp_tcp_port\fR configuration
+parameter (default value of 24) will be used.
+An IPv6 address must be formatted as [\fBipv6\fR:\fIaddress\fR].
+.SH "SINGLE-RECIPIENT DELIVERY"
+.na
+.nf
+.ad
+.fi
+By default, the Postfix SMTP+LMTP client delivers mail to
+multiple recipients per delivery request. This is undesirable
+when prepending a \fBDelivered\-to:\fR or \fBX\-Original\-To:\fR
+message header. To prevent Postfix from sending multiple
+recipients per delivery request, specify
+.sp
+.nf
+    \fItransport\fB_destination_recipient_limit = 1\fR
+.fi
+
+in the Postfix \fBmain.cf\fR file, where \fItransport\fR
+is the name in the first column of the Postfix \fBmaster.cf\fR
+entry for this mail delivery service.
+.SH "COMMAND ATTRIBUTE SYNTAX"
+.na
+.nf
+.ad
+.fi
+.IP "\fBflags=DORX\fR (optional)"
+Optional message processing flags.
+.RS
+.IP \fBD\fR
+Prepend a "\fBDelivered\-To: \fIrecipient\fR" message header
+with the envelope recipient address. Note: for this to work,
+the \fItransport\fB_destination_recipient_limit\fR must be
+1 (see SINGLE\-RECIPIENT DELIVERY above for details).
+.sp
+The \fBD\fR flag also enforces loop detection: if a message
+already contains a \fBDelivered\-To:\fR header with the same
+recipient address, then the message is returned as
+undeliverable. The address comparison is case insensitive.
+.sp
+This feature is available as of Postfix 3.5.
+.IP \fBO\fR
+Prepend an "\fBX\-Original\-To: \fIrecipient\fR" message
+header with the recipient address as given to Postfix. Note:
+for this to work, the
+\fItransport\fB_destination_recipient_limit\fR must be 1
+(see SINGLE\-RECIPIENT DELIVERY above for details).
+.sp
+This feature is available as of Postfix 3.5.
+.IP \fBR\fR
+Prepend a "\fBReturn\-Path: <\fIsender\fB>\fR" message header
+with the envelope sender address.
+.sp
+This feature is available as of Postfix 3.5.
+.IP \fBX\fR
+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".
+.sp
+This feature is available as of Postfix 3.5.
+.RE
+.SH "SECURITY"
+.na
+.nf
+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.
+.SH "STANDARDS"
+.na
+.nf
+RFC 821 (SMTP protocol)
+RFC 822 (ARPA Internet Text Messages)
+RFC 1651 (SMTP service extensions)
+RFC 1652 (8bit\-MIME transport)
+RFC 1870 (Message Size Declaration)
+RFC 2033 (LMTP protocol)
+RFC 2034 (SMTP Enhanced Error Codes)
+RFC 2045 (MIME: Format of Internet Message Bodies)
+RFC 2046 (MIME: Media Types)
+RFC 2554 (AUTH command)
+RFC 2821 (SMTP protocol)
+RFC 2920 (SMTP Pipelining)
+RFC 3207 (STARTTLS command)
+RFC 3461 (SMTP DSN Extension)
+RFC 3463 (Enhanced Status Codes)
+RFC 4954 (AUTH command)
+RFC 5321 (SMTP protocol)
+RFC 6531 (Internationalized SMTP)
+RFC 6533 (Internationalized Delivery Status Notifications)
+RFC 7672 (SMTP security via opportunistic DANE TLS)
+.SH DIAGNOSTICS
+.ad
+.fi
+Problems and transactions are logged to \fBsyslogd\fR(8)
+or \fBpostlogd\fR(8).
+Corrupted message files are marked so that the queue manager can
+move them to the \fBcorrupt\fR queue for further inspection.
+
+Depending on the setting of the \fBnotify_classes\fR parameter,
+the postmaster is notified of bounces, protocol problems, and of
+other trouble.
+.SH BUGS
+.ad
+.fi
+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.
+.SH "CONFIGURATION PARAMETERS"
+.na
+.nf
+.ad
+.fi
+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_\fIxxx\fR configuration parameters have an
+lmtp_\fIxxx\fR "mirror" parameter for the equivalent LMTP
+feature. This document describes only those LMTP\-related
+parameters that aren't simply "mirror" parameters.
+
+Changes to \fBmain.cf\fR are picked up automatically, as \fBsmtp\fR(8)
+processes run for only a limited amount of time. Use the command
+"\fBpostfix reload\fR" to speed up a change.
+
+The text below provides only a parameter summary. See
+\fBpostconf\fR(5) for more details including examples.
+.SH "COMPATIBILITY CONTROLS"
+.na
+.nf
+.ad
+.fi
+.IP "\fBignore_mx_lookup_error (no)\fR"
+Ignore DNS MX lookups that produce no response.
+.IP "\fBsmtp_always_send_ehlo (yes)\fR"
+Always send EHLO at the start of an SMTP session.
+.IP "\fBsmtp_never_send_ehlo (no)\fR"
+Never send EHLO at the start of an SMTP session.
+.IP "\fBsmtp_defer_if_no_mx_address_found (no)\fR"
+Defer mail delivery when no MX record resolves to an IP address.
+.IP "\fBsmtp_line_length_limit (998)\fR"
+The maximal length of message header and body lines that Postfix
+will send via SMTP.
+.IP "\fBsmtp_pix_workaround_delay_time (10s)\fR"
+How long the Postfix SMTP client pauses before sending
+".<CR><LF>" in order to work around the PIX firewall
+"<CR><LF>.<CR><LF>" bug.
+.IP "\fBsmtp_pix_workaround_threshold_time (500s)\fR"
+How long a message must be queued before the Postfix SMTP client
+turns on the PIX firewall "<CR><LF>.<CR><LF>"
+bug workaround for delivery through firewalls with "smtp fixup"
+mode turned on.
+.IP "\fBsmtp_pix_workarounds (disable_esmtp, delay_dotcrlf)\fR"
+A list that specifies zero or more workarounds for CISCO PIX
+firewall bugs.
+.IP "\fBsmtp_pix_workaround_maps (empty)\fR"
+Lookup tables, indexed by the remote SMTP server address, with
+per\-destination workarounds for CISCO PIX firewall bugs.
+.IP "\fBsmtp_quote_rfc821_envelope (yes)\fR"
+Quote addresses in Postfix SMTP client MAIL FROM and RCPT TO commands
+as required
+by RFC 5321.
+.IP "\fBsmtp_reply_filter (empty)\fR"
+A mechanism to transform replies from remote SMTP servers one
+line at a time.
+.IP "\fBsmtp_skip_5xx_greeting (yes)\fR"
+Skip remote SMTP servers that greet with a 5XX status code.
+.IP "\fBsmtp_skip_quit_response (yes)\fR"
+Do not wait for the response to the SMTP QUIT command.
+.PP
+Available in Postfix version 2.0 and earlier:
+.IP "\fBsmtp_skip_4xx_greeting (yes)\fR"
+Skip SMTP servers that greet with a 4XX status code (go away, try
+again later).
+.PP
+Available in Postfix version 2.2 and later:
+.IP "\fBsmtp_discard_ehlo_keyword_address_maps (empty)\fR"
+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.
+.IP "\fBsmtp_discard_ehlo_keywords (empty)\fR"
+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.
+.IP "\fBsmtp_generic_maps (empty)\fR"
+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.
+.PP
+Available in Postfix version 2.2.9 and later:
+.IP "\fBsmtp_cname_overrides_servername (version dependent)\fR"
+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.
+.PP
+Available in Postfix version 2.3 and later:
+.IP "\fBlmtp_discard_lhlo_keyword_address_maps (empty)\fR"
+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.
+.IP "\fBlmtp_discard_lhlo_keywords (empty)\fR"
+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.
+.PP
+Available in Postfix version 2.4.4 and later:
+.IP "\fBsend_cyrus_sasl_authzid (no)\fR"
+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 authcid's password.
+.PP
+Available in Postfix version 2.5 and later:
+.IP "\fBsmtp_header_checks (empty)\fR"
+Restricted \fBheader_checks\fR(5) tables for the Postfix SMTP client.
+.IP "\fBsmtp_mime_header_checks (empty)\fR"
+Restricted \fBmime_header_checks\fR(5) tables for the Postfix SMTP
+client.
+.IP "\fBsmtp_nested_header_checks (empty)\fR"
+Restricted \fBnested_header_checks\fR(5) tables for the Postfix SMTP
+client.
+.IP "\fBsmtp_body_checks (empty)\fR"
+Restricted \fBbody_checks\fR(5) tables for the Postfix SMTP client.
+.PP
+Available in Postfix version 2.6 and later:
+.IP "\fBtcp_windowsize (0)\fR"
+An optional workaround for routers that break TCP window scaling.
+.PP
+Available in Postfix version 2.8 and later:
+.IP "\fBsmtp_dns_resolver_options (empty)\fR"
+DNS Resolver options for the Postfix SMTP client.
+.PP
+Available in Postfix version 2.9 \- 3.6:
+.IP "\fBsmtp_per_record_deadline (no)\fR"
+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 message).
+.PP
+Available in Postfix version 2.9 and later:
+.IP "\fBsmtp_send_dummy_mail_auth (no)\fR"
+Whether or not to append the "AUTH=<>" option to the MAIL
+FROM command in SASL\-authenticated SMTP sessions.
+.PP
+Available in Postfix version 2.11 and later:
+.IP "\fBsmtp_dns_support_level (empty)\fR"
+Level of DNS support in the Postfix SMTP client.
+.PP
+Available in Postfix version 3.0 and later:
+.IP "\fBsmtp_delivery_status_filter ($default_delivery_status_filter)\fR"
+Optional filter for the \fBsmtp\fR(8) delivery agent to change the
+delivery status code or explanatory text of successful or unsuccessful
+deliveries.
+.IP "\fBsmtp_dns_reply_filter (empty)\fR"
+Optional filter for Postfix SMTP client DNS lookup results.
+.PP
+Available in Postfix version 3.3 and later:
+.IP "\fBsmtp_balance_inet_protocols (yes)\fR"
+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 smtp_mx_address_limit.
+.PP
+Available in Postfix 3.5 and later:
+.IP "\fBinfo_log_address_format (external)\fR"
+The email address form that will be used in non\-debug logging
+(info, warning, etc.).
+.PP
+Available in Postfix 3.6 and later:
+.IP "\fBdnssec_probe (ns:.)\fR"
+The DNS query type (default: "ns") and DNS query name (default:
+".") that Postfix may use to determine whether DNSSEC validation
+is available.
+.IP "\fBknown_tcp_ports (lmtp=24, smtp=25, smtps=submissions=465, submission=587)\fR"
+Optional setting that avoids lookups in the \fBservices\fR(5) database.
+.PP
+Available in Postfix version 3.7 and later:
+.IP "\fBsmtp_per_request_deadline (no)\fR"
+Change the behavior of the smtp_*_timeout time limits, from a
+time limit per plaintext or TLS read or write call, to a combined
+time limit for sending a complete SMTP request and for receiving a
+complete SMTP response.
+.IP "\fBsmtp_min_data_rate (500)\fR"
+The minimum plaintext data transfer rate in bytes/second for
+DATA requests, when deadlines are enabled with smtp_per_request_deadline.
+.IP "\fBheader_from_format (standard)\fR"
+The format of the Postfix\-generated \fBFrom:\fR header.
+.SH "MIME PROCESSING CONTROLS"
+.na
+.nf
+.ad
+.fi
+Available in Postfix version 2.0 and later:
+.IP "\fBdisable_mime_output_conversion (no)\fR"
+Disable the conversion of 8BITMIME format to 7BIT format.
+.IP "\fBmime_boundary_length_limit (2048)\fR"
+The maximal length of MIME multipart boundary strings.
+.IP "\fBmime_nesting_limit (100)\fR"
+The maximal recursion level that the MIME processor will handle.
+.SH "EXTERNAL CONTENT INSPECTION CONTROLS"
+.na
+.nf
+.ad
+.fi
+Available in Postfix version 2.1 and later:
+.IP "\fBsmtp_send_xforward_command (no)\fR"
+Send the non\-standard XFORWARD command when the Postfix SMTP server
+EHLO response announces XFORWARD support.
+.SH "SASL AUTHENTICATION CONTROLS"
+.na
+.nf
+.ad
+.fi
+.IP "\fBsmtp_sasl_auth_enable (no)\fR"
+Enable SASL authentication in the Postfix SMTP client.
+.IP "\fBsmtp_sasl_password_maps (empty)\fR"
+Optional Postfix SMTP client lookup tables with one username:password
+entry per sender, remote hostname or next\-hop domain.
+.IP "\fBsmtp_sasl_security_options (noplaintext, noanonymous)\fR"
+Postfix SMTP client SASL security options; as of Postfix 2.3
+the list of available
+features depends on the SASL client implementation that is selected
+with \fBsmtp_sasl_type\fR.
+.PP
+Available in Postfix version 2.2 and later:
+.IP "\fBsmtp_sasl_mechanism_filter (empty)\fR"
+If non\-empty, a Postfix SMTP client filter for the remote SMTP
+server's list of offered SASL mechanisms.
+.PP
+Available in Postfix version 2.3 and later:
+.IP "\fBsmtp_sender_dependent_authentication (no)\fR"
+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 different senders will use the
+appropriate credentials.
+.IP "\fBsmtp_sasl_path (empty)\fR"
+Implementation\-specific information that the Postfix SMTP client
+passes through to
+the SASL plug\-in implementation that is selected with
+\fBsmtp_sasl_type\fR.
+.IP "\fBsmtp_sasl_type (cyrus)\fR"
+The SASL plug\-in type that the Postfix SMTP client should use
+for authentication.
+.PP
+Available in Postfix version 2.5 and later:
+.IP "\fBsmtp_sasl_auth_cache_name (empty)\fR"
+An optional table to prevent repeated SASL authentication
+failures with the same remote SMTP server hostname, username and
+password.
+.IP "\fBsmtp_sasl_auth_cache_time (90d)\fR"
+The maximal age of an smtp_sasl_auth_cache_name entry before it
+is removed.
+.IP "\fBsmtp_sasl_auth_soft_bounce (yes)\fR"
+When a remote SMTP server rejects a SASL authentication request
+with a 535 reply code, defer mail delivery instead of returning
+mail as undeliverable.
+.PP
+Available in Postfix version 2.9 and later:
+.IP "\fBsmtp_send_dummy_mail_auth (no)\fR"
+Whether or not to append the "AUTH=<>" option to the MAIL
+FROM command in SASL\-authenticated SMTP sessions.
+.SH "STARTTLS SUPPORT CONTROLS"
+.na
+.nf
+.ad
+.fi
+Detailed information about STARTTLS configuration may be found
+in the TLS_README document.
+.IP "\fBsmtp_tls_security_level (empty)\fR"
+The default SMTP TLS security level for the Postfix SMTP client;
+when a non\-empty value is specified, this overrides the obsolete
+parameters smtp_use_tls, smtp_enforce_tls, and smtp_tls_enforce_peername.
+.IP "\fBsmtp_sasl_tls_security_options ($smtp_sasl_security_options)\fR"
+The SASL authentication security options that the Postfix SMTP
+client uses for TLS encrypted SMTP sessions.
+.IP "\fBsmtp_starttls_timeout (300s)\fR"
+Time limit for Postfix SMTP client write and read operations
+during TLS startup and shutdown handshake procedures.
+.IP "\fBsmtp_tls_CAfile (empty)\fR"
+A file containing CA certificates of root CAs trusted to sign
+either remote SMTP server certificates or intermediate CA certificates.
+.IP "\fBsmtp_tls_CApath (empty)\fR"
+Directory with PEM format Certification Authority certificates
+that the Postfix SMTP client uses to verify a remote SMTP server
+certificate.
+.IP "\fBsmtp_tls_cert_file (empty)\fR"
+File with the Postfix SMTP client RSA certificate in PEM format.
+.IP "\fBsmtp_tls_mandatory_ciphers (medium)\fR"
+The minimum TLS cipher grade that the Postfix SMTP client will
+use with
+mandatory TLS encryption.
+.IP "\fBsmtp_tls_exclude_ciphers (empty)\fR"
+List of ciphers or cipher types to exclude from the Postfix
+SMTP client cipher
+list at all TLS security levels.
+.IP "\fBsmtp_tls_mandatory_exclude_ciphers (empty)\fR"
+Additional list of ciphers or cipher types to exclude from the
+Postfix SMTP client cipher list at mandatory TLS security levels.
+.IP "\fBsmtp_tls_dcert_file (empty)\fR"
+File with the Postfix SMTP client DSA certificate in PEM format.
+.IP "\fBsmtp_tls_dkey_file ($smtp_tls_dcert_file)\fR"
+File with the Postfix SMTP client DSA private key in PEM format.
+.IP "\fBsmtp_tls_key_file ($smtp_tls_cert_file)\fR"
+File with the Postfix SMTP client RSA private key in PEM format.
+.IP "\fBsmtp_tls_loglevel (0)\fR"
+Enable additional Postfix SMTP client logging of TLS activity.
+.IP "\fBsmtp_tls_note_starttls_offer (no)\fR"
+Log the hostname of a remote SMTP server that offers STARTTLS,
+when TLS is not already enabled for that server.
+.IP "\fBsmtp_tls_policy_maps (empty)\fR"
+Optional lookup tables with the Postfix SMTP client TLS security
+policy by next\-hop destination; when a non\-empty value is specified,
+this overrides the obsolete smtp_tls_per_site parameter.
+.IP "\fBsmtp_tls_mandatory_protocols (see 'postconf -d' output)\fR"
+TLS protocols that the Postfix SMTP client will use with mandatory
+TLS encryption.
+.IP "\fBsmtp_tls_scert_verifydepth (9)\fR"
+The verification depth for remote SMTP server certificates.
+.IP "\fBsmtp_tls_secure_cert_match (nexthop, dot\-nexthop)\fR"
+How the Postfix SMTP client verifies the server certificate
+peername for the "secure" TLS security level.
+.IP "\fBsmtp_tls_session_cache_database (empty)\fR"
+Name of the file containing the optional Postfix SMTP client
+TLS session cache.
+.IP "\fBsmtp_tls_session_cache_timeout (3600s)\fR"
+The expiration time of Postfix SMTP client TLS session cache
+information.
+.IP "\fBsmtp_tls_verify_cert_match (hostname)\fR"
+How the Postfix SMTP client verifies the server certificate
+peername for the
+"verify" TLS security level.
+.IP "\fBtls_daemon_random_bytes (32)\fR"
+The number of pseudo\-random bytes that an \fBsmtp\fR(8) or \fBsmtpd\fR(8)
+process requests from the \fBtlsmgr\fR(8) server in order to seed its
+internal pseudo random number generator (PRNG).
+.IP "\fBtls_high_cipherlist (see 'postconf -d' output)\fR"
+The OpenSSL cipherlist for "high" grade ciphers.
+.IP "\fBtls_medium_cipherlist (see 'postconf -d' output)\fR"
+The OpenSSL cipherlist for "medium" or higher grade ciphers.
+.IP "\fBtls_low_cipherlist (see 'postconf -d' output)\fR"
+The OpenSSL cipherlist for "low" or higher grade ciphers.
+.IP "\fBtls_export_cipherlist (see 'postconf -d' output)\fR"
+The OpenSSL cipherlist for "export" or higher grade ciphers.
+.IP "\fBtls_null_cipherlist (eNULL:!aNULL)\fR"
+The OpenSSL cipherlist for "NULL" grade ciphers that provide
+authentication without encryption.
+.PP
+Available in Postfix version 2.4 and later:
+.IP "\fBsmtp_sasl_tls_verified_security_options ($smtp_sasl_tls_security_options)\fR"
+The SASL authentication security options that the Postfix SMTP
+client uses for TLS encrypted SMTP sessions with a verified server
+certificate.
+.PP
+Available in Postfix version 2.5 and later:
+.IP "\fBsmtp_tls_fingerprint_cert_match (empty)\fR"
+List of acceptable remote SMTP server certificate fingerprints for
+the "fingerprint" TLS security level (\fBsmtp_tls_security_level\fR =
+fingerprint).
+.IP "\fBsmtp_tls_fingerprint_digest (see 'postconf -d' output)\fR"
+The message digest algorithm used to construct remote SMTP server
+certificate fingerprints.
+.PP
+Available in Postfix version 2.6 and later:
+.IP "\fBsmtp_tls_protocols (see postconf -d output)\fR"
+TLS protocols that the Postfix SMTP client will use with
+opportunistic TLS encryption.
+.IP "\fBsmtp_tls_ciphers (medium)\fR"
+The minimum TLS cipher grade that the Postfix SMTP client
+will use with opportunistic TLS encryption.
+.IP "\fBsmtp_tls_eccert_file (empty)\fR"
+File with the Postfix SMTP client ECDSA certificate in PEM format.
+.IP "\fBsmtp_tls_eckey_file ($smtp_tls_eccert_file)\fR"
+File with the Postfix SMTP client ECDSA private key in PEM format.
+.PP
+Available in Postfix version 2.7 and later:
+.IP "\fBsmtp_tls_block_early_mail_reply (no)\fR"
+Try to detect a mail hijacking attack based on a TLS protocol
+vulnerability (CVE\-2009\-3555), where an attacker prepends malicious
+HELO, MAIL, RCPT, DATA commands to a Postfix SMTP client TLS session.
+.PP
+Available in Postfix version 2.8 and later:
+.IP "\fBtls_disable_workarounds (see 'postconf -d' output)\fR"
+List or bit\-mask of OpenSSL bug work\-arounds to disable.
+.PP
+Available in Postfix version 2.11\-3.1:
+.IP "\fBtls_dane_digest_agility (on)\fR"
+Configure RFC7671 DANE TLSA digest algorithm agility.
+.IP "\fBtls_dane_trust_anchor_digest_enable (yes)\fR"
+Enable support for RFC 6698 (DANE TLSA) DNS records that contain
+digests of trust\-anchors with certificate usage "2".
+.PP
+Available in Postfix version 2.11 and later:
+.IP "\fBsmtp_tls_trust_anchor_file (empty)\fR"
+Zero or more PEM\-format files with trust\-anchor certificates
+and/or public keys.
+.IP "\fBsmtp_tls_force_insecure_host_tlsa_lookup (no)\fR"
+Lookup the associated DANE TLSA RRset even when a hostname is
+not an alias and its address records lie in an unsigned zone.
+.IP "\fBtlsmgr_service_name (tlsmgr)\fR"
+The name of the \fBtlsmgr\fR(8) service entry in master.cf.
+.PP
+Available in Postfix version 3.0 and later:
+.IP "\fBsmtp_tls_wrappermode (no)\fR"
+Request that the Postfix SMTP client connects using the
+legacy SMTPS protocol instead of using the STARTTLS command.
+.PP
+Available in Postfix version 3.1 and later:
+.IP "\fBsmtp_tls_dane_insecure_mx_policy (see 'postconf -d' output)\fR"
+The TLS policy for MX hosts with "secure" TLSA records when the
+nexthop destination security level is \fBdane\fR, but the MX
+record was found via an "insecure" MX lookup.
+.PP
+Available in Postfix version 3.4 and later:
+.IP "\fBsmtp_tls_connection_reuse (no)\fR"
+Try to make multiple deliveries per TLS\-encrypted connection.
+.IP "\fBsmtp_tls_chain_files (empty)\fR"
+List of one or more PEM files, each holding one or more private keys
+directly followed by a corresponding certificate chain.
+.IP "\fBsmtp_tls_servername (empty)\fR"
+Optional name to send to the remote SMTP server in the TLS Server
+Name Indication (SNI) extension.
+.PP
+Available in Postfix 3.5, 3.4.6, 3.3.5, 3.2.10, 3.1.13 and later:
+.IP "\fBtls_fast_shutdown_enable (yes)\fR"
+A workaround for implementations that hang Postfix while shutting
+down a TLS session, until Postfix times out.
+.PP
+Available in Postfix 3.9, 3.8.1, 3.7.6, 3.6.10, 3.5.20 and later:
+.IP "\fBtls_config_file (default)\fR"
+Optional configuration file with baseline OpenSSL settings.
+.IP "\fBtls_config_name (empty)\fR"
+The application name passed by Postfix to OpenSSL library
+initialization functions.
+.SH "OBSOLETE STARTTLS CONTROLS"
+.na
+.nf
+.ad
+.fi
+The following configuration parameters exist for compatibility
+with Postfix versions before 2.3. Support for these will
+be removed in a future release.
+.IP "\fBsmtp_use_tls (no)\fR"
+Opportunistic mode: use TLS when a remote SMTP server announces
+STARTTLS support, otherwise send the mail in the clear.
+.IP "\fBsmtp_enforce_tls (no)\fR"
+Enforcement mode: require that remote SMTP servers use TLS
+encryption, and never send mail in the clear.
+.IP "\fBsmtp_tls_enforce_peername (yes)\fR"
+With mandatory TLS encryption, require that the remote SMTP
+server hostname matches the information in the remote SMTP server
+certificate.
+.IP "\fBsmtp_tls_per_site (empty)\fR"
+Optional lookup tables with the Postfix SMTP client TLS usage
+policy by next\-hop destination and by remote SMTP server hostname.
+.IP "\fBsmtp_tls_cipherlist (empty)\fR"
+Obsolete Postfix < 2.3 control for the Postfix SMTP client TLS
+cipher list.
+.SH "RESOURCE AND RATE CONTROLS"
+.na
+.nf
+.ad
+.fi
+.IP "\fBsmtp_connect_timeout (30s)\fR"
+The Postfix SMTP client time limit for completing a TCP connection, or
+zero (use the operating system built\-in time limit).
+.IP "\fBsmtp_helo_timeout (300s)\fR"
+The Postfix SMTP client time limit for sending the HELO or EHLO command,
+and for receiving the initial remote SMTP server response.
+.IP "\fBlmtp_lhlo_timeout (300s)\fR"
+The Postfix LMTP client time limit for sending the LHLO command,
+and for receiving the initial remote LMTP server response.
+.IP "\fBsmtp_xforward_timeout (300s)\fR"
+The Postfix SMTP client time limit for sending the XFORWARD command,
+and for receiving the remote SMTP server response.
+.IP "\fBsmtp_mail_timeout (300s)\fR"
+The Postfix SMTP client time limit for sending the MAIL FROM command,
+and for receiving the remote SMTP server response.
+.IP "\fBsmtp_rcpt_timeout (300s)\fR"
+The Postfix SMTP client time limit for sending the SMTP RCPT TO
+command, and for receiving the remote SMTP server response.
+.IP "\fBsmtp_data_init_timeout (120s)\fR"
+The Postfix SMTP client time limit for sending the SMTP DATA command,
+and for receiving the remote SMTP server response.
+.IP "\fBsmtp_data_xfer_timeout (180s)\fR"
+The Postfix SMTP client time limit for sending the SMTP message content.
+.IP "\fBsmtp_data_done_timeout (600s)\fR"
+The Postfix SMTP client time limit for sending the SMTP ".", and
+for receiving the remote SMTP server response.
+.IP "\fBsmtp_quit_timeout (300s)\fR"
+The Postfix SMTP client time limit for sending the QUIT command,
+and for receiving the remote SMTP server response.
+.PP
+Available in Postfix version 2.1 and later:
+.IP "\fBsmtp_mx_address_limit (5)\fR"
+The maximal number of MX (mail exchanger) IP addresses that can
+result from Postfix SMTP client mail exchanger lookups, or zero (no
+limit).
+.IP "\fBsmtp_mx_session_limit (2)\fR"
+The maximal number of SMTP sessions per delivery request before
+the Postfix SMTP client
+gives up or delivers to a fall\-back relay host, or zero (no
+limit).
+.IP "\fBsmtp_rset_timeout (20s)\fR"
+The Postfix SMTP client time limit for sending the RSET command,
+and for receiving the remote SMTP server response.
+.PP
+Available in Postfix version 2.2 and earlier:
+.IP "\fBlmtp_cache_connection (yes)\fR"
+Keep Postfix LMTP client connections open for up to $max_idle
+seconds.
+.PP
+Available in Postfix version 2.2 and later:
+.IP "\fBsmtp_connection_cache_destinations (empty)\fR"
+Permanently enable SMTP connection caching for the specified
+destinations.
+.IP "\fBsmtp_connection_cache_on_demand (yes)\fR"
+Temporarily enable SMTP connection caching while a destination
+has a high volume of mail in the active queue.
+.IP "\fBsmtp_connection_reuse_time_limit (300s)\fR"
+The amount of time during which Postfix will use an SMTP
+connection repeatedly.
+.IP "\fBsmtp_connection_cache_time_limit (2s)\fR"
+When SMTP connection caching is enabled, the amount of time that
+an unused SMTP client socket is kept open before it is closed.
+.PP
+Available in Postfix version 2.3 and later:
+.IP "\fBconnection_cache_protocol_timeout (5s)\fR"
+Time limit for connection cache connect, send or receive
+operations.
+.PP
+Available in Postfix version 2.9 \- 3.6:
+.IP "\fBsmtp_per_record_deadline (no)\fR"
+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 message).
+.PP
+Available in Postfix version 2.11 and later:
+.IP "\fBsmtp_connection_reuse_count_limit (0)\fR"
+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).
+.PP
+Available in Postfix version 3.4 and later:
+.IP "\fBsmtp_tls_connection_reuse (no)\fR"
+Try to make multiple deliveries per TLS\-encrypted connection.
+.PP
+Available in Postfix version 3.7 and later:
+.IP "\fBsmtp_per_request_deadline (no)\fR"
+Change the behavior of the smtp_*_timeout time limits, from a
+time limit per plaintext or TLS read or write call, to a combined
+time limit for sending a complete SMTP request and for receiving a
+complete SMTP response.
+.IP "\fBsmtp_min_data_rate (500)\fR"
+The minimum plaintext data transfer rate in bytes/second for
+DATA requests, when deadlines are enabled with smtp_per_request_deadline.
+.PP
+Implemented in the qmgr(8) daemon:
+.IP "\fBtransport_destination_concurrency_limit ($default_destination_concurrency_limit)\fR"
+A transport\-specific override for the
+default_destination_concurrency_limit parameter value, where
+\fItransport\fR is the master.cf name of the message delivery
+transport.
+.IP "\fBtransport_destination_recipient_limit ($default_destination_recipient_limit)\fR"
+A transport\-specific override for the
+default_destination_recipient_limit parameter value, where
+\fItransport\fR is the master.cf name of the message delivery
+transport.
+.SH "SMTPUTF8 CONTROLS"
+.na
+.nf
+.ad
+.fi
+Preliminary SMTPUTF8 support is introduced with Postfix 3.0.
+.IP "\fBsmtputf8_enable (yes)\fR"
+Enable preliminary SMTPUTF8 support for the protocols described
+in RFC 6531..6533.
+.IP "\fBsmtputf8_autodetect_classes (sendmail, verify)\fR"
+Detect that a message requires SMTPUTF8 support for the specified
+mail origin classes.
+.PP
+Available in Postfix version 3.2 and later:
+.IP "\fBenable_idna2003_compatibility (no)\fR"
+Enable 'transitional' compatibility between IDNA2003 and IDNA2008,
+when converting UTF\-8 domain names to/from the ASCII form that is
+used for DNS lookups.
+.SH "TROUBLE SHOOTING CONTROLS"
+.na
+.nf
+.ad
+.fi
+.IP "\fBdebug_peer_level (2)\fR"
+The increment in verbose logging level when a nexthop destination,
+remote client or server name or network address matches a pattern
+given with the debug_peer_list parameter.
+.IP "\fBdebug_peer_list (empty)\fR"
+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 $debug_peer_level.
+.IP "\fBerror_notice_recipient (postmaster)\fR"
+The recipient of postmaster notifications about mail delivery
+problems that are caused by policy, resource, software or protocol
+errors.
+.IP "\fBinternal_mail_filter_classes (empty)\fR"
+What categories of Postfix\-generated mail are subject to
+before\-queue content inspection by non_smtpd_milters, header_checks
+and body_checks.
+.IP "\fBnotify_classes (resource, software)\fR"
+The list of error classes that are reported to the postmaster.
+.SH "MISCELLANEOUS CONTROLS"
+.na
+.nf
+.ad
+.fi
+.IP "\fBbest_mx_transport (empty)\fR"
+Where the Postfix SMTP client should deliver mail when it detects
+a "mail loops back to myself" error condition.
+.IP "\fBconfig_directory (see 'postconf -d' output)\fR"
+The default location of the Postfix main.cf and master.cf
+configuration files.
+.IP "\fBdaemon_timeout (18000s)\fR"
+How much time a Postfix daemon process may take to handle a
+request before it is terminated by a built\-in watchdog timer.
+.IP "\fBdelay_logging_resolution_limit (2)\fR"
+The maximal number of digits after the decimal point when logging
+sub\-second delay values.
+.IP "\fBdisable_dns_lookups (no)\fR"
+Disable DNS lookups in the Postfix SMTP and LMTP clients.
+.IP "\fBinet_interfaces (all)\fR"
+The network interface addresses that this mail system receives
+mail on.
+.IP "\fBinet_protocols (see 'postconf -d output')\fR"
+The Internet protocols Postfix will attempt to use when making
+or accepting connections.
+.IP "\fBipc_timeout (3600s)\fR"
+The time limit for sending or receiving information over an internal
+communication channel.
+.IP "\fBlmtp_assume_final (no)\fR"
+When a remote LMTP server announces no DSN support, assume that
+the
+server performs final delivery, and send "delivered" delivery status
+notifications instead of "relayed".
+.IP "\fBlmtp_tcp_port (24)\fR"
+The default TCP port that the Postfix LMTP client connects to.
+.IP "\fBmax_idle (100s)\fR"
+The maximum amount of time that an idle Postfix daemon process waits
+for an incoming connection before terminating voluntarily.
+.IP "\fBmax_use (100)\fR"
+The maximal number of incoming connections that a Postfix daemon
+process will service before terminating voluntarily.
+.IP "\fBprocess_id (read\-only)\fR"
+The process ID of a Postfix command or daemon process.
+.IP "\fBprocess_name (read\-only)\fR"
+The process name of a Postfix command or daemon process.
+.IP "\fBproxy_interfaces (empty)\fR"
+The network interface addresses that this mail system receives mail
+on by way of a proxy or network address translation unit.
+.IP "\fBsmtp_address_preference (any)\fR"
+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.
+.IP "\fBsmtp_bind_address (empty)\fR"
+An optional numerical network address that the Postfix SMTP client
+should bind to when making an IPv4 connection.
+.IP "\fBsmtp_bind_address6 (empty)\fR"
+An optional numerical network address that the Postfix SMTP client
+should bind to when making an IPv6 connection.
+.IP "\fBsmtp_helo_name ($myhostname)\fR"
+The hostname to send in the SMTP HELO or EHLO command.
+.IP "\fBlmtp_lhlo_name ($myhostname)\fR"
+The hostname to send in the LMTP LHLO command.
+.IP "\fBsmtp_host_lookup (dns)\fR"
+What mechanisms the Postfix SMTP client uses to look up a host's
+IP address.
+.IP "\fBsmtp_randomize_addresses (yes)\fR"
+Randomize the order of equal\-preference MX host addresses.
+.IP "\fBsyslog_facility (mail)\fR"
+The syslog facility of Postfix logging.
+.IP "\fBsyslog_name (see 'postconf -d' output)\fR"
+A prefix that is prepended to the process name in syslog
+records, so that, for example, "smtpd" becomes "prefix/smtpd".
+.PP
+Available with Postfix 2.2 and earlier:
+.IP "\fBfallback_relay (empty)\fR"
+Optional list of relay hosts for SMTP destinations that can't be
+found or that are unreachable.
+.PP
+Available with Postfix 2.3 and later:
+.IP "\fBsmtp_fallback_relay ($fallback_relay)\fR"
+Optional list of relay hosts for SMTP destinations that can't be
+found or that are unreachable.
+.PP
+Available with Postfix 3.0 and later:
+.IP "\fBsmtp_address_verify_target (rcpt)\fR"
+In the context of email address verification, the SMTP protocol
+stage that determines whether an email address is deliverable.
+.PP
+Available with Postfix 3.1 and later:
+.IP "\fBlmtp_fallback_relay (empty)\fR"
+Optional list of relay hosts for LMTP destinations that can't be
+found or that are unreachable.
+.PP
+Available with Postfix 3.2 and later:
+.IP "\fBsmtp_tcp_port (smtp)\fR"
+The default TCP port that the Postfix SMTP client connects to.
+.PP
+Available in Postfix 3.3 and later:
+.IP "\fBservice_name (read\-only)\fR"
+The master.cf service name of a Postfix daemon process.
+.PP
+Available in Postfix 3.7 and later:
+.IP "\fBsmtp_bind_address_enforce (no)\fR"
+Defer delivery when the Postfix SMTP client cannot apply the
+smtp_bind_address or smtp_bind_address6 setting.
+.SH "SEE ALSO"
+.na
+.nf
+generic(5), output address rewriting
+header_checks(5), message header content inspection
+body_checks(5), body parts content inspection
+qmgr(8), queue manager
+bounce(8), delivery status reports
+scache(8), connection cache server
+postconf(5), configuration parameters
+master(5), generic daemon options
+master(8), process manager
+tlsmgr(8), TLS session and PRNG management
+postlogd(8), Postfix logging
+syslogd(8), system logging
+.SH "README FILES"
+.na
+.nf
+.ad
+.fi
+Use "\fBpostconf readme_directory\fR" or
+"\fBpostconf html_directory\fR" to locate this information.
+.na
+.nf
+SASL_README, Postfix SASL howto
+TLS_README, Postfix STARTTLS howto
+.SH "LICENSE"
+.na
+.nf
+.ad
+.fi
+The Secure Mailer license must be distributed with this software.
+.SH "AUTHOR(S)"
+.na
+.nf
+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