SMTP(8)			    System Manager's Manual		       SMTP(8)



NAME
       smtp - Postfix SMTP+LMTP client

SYNOPSIS
       smtp [generic Postfix daemon options]

DESCRIPTION
       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 master(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
       bounce(8), defer(8) or trace(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
       scache(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.

SMTP DESTINATION SYNTAX
       SMTP destinations have the following form:

       domainname

       domainname:port
	      Look up the mail exchangers for the specified domain,  and  con-
	      nect to the specified port (default: smtp).

       [hostname]

       [hostname]:port
	      Look  up	the  address(es) of the specified host, and connect to
	      the specified port (default: smtp).

       [address]

       [address]:port
	      Connect to the host at the specified address, and connect to the
	      specified	 port (default: smtp). An IPv6 address must be format-
	      ted as [ipv6:address].

LMTP DESTINATION SYNTAX
       LMTP destinations have the following form:

       unix:pathname
	      Connect to the local UNIX-domain server that  is	bound  to  the
	      specified	 pathname.  If	the process runs chrooted, an absolute
	      pathname is interpreted relative to the Postfix queue directory.

       inet:hostname

       inet:hostname:port

       inet:[address]

       inet:[address]:port
	      Connect to the specified TCP port	 on  the  specified  local  or
	      remote  host.  If	 no  port  is  specified,  connect to the port
	      defined as lmtp in services(4).  If no such  service  is	found,
	      the  lmtp_tcp_port configuration parameter (default value of 24)
	      will  be	used.	An  IPv6  address   must   be	formatted   as
	      [ipv6:address].

SECURITY
       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.

STANDARDS
       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)

DIAGNOSTICS
       Problems	 and transactions are logged to syslogd(8).  Corrupted message
       files are marked so that the queue manager can move them to the corrupt
       queue for further inspection.

       Depending  on the setting of the notify_classes parameter, the postmas-
       ter is notified of bounces, protocol problems, and of other trouble.

BUGS
       SMTP and LMTP connection caching does not work with TLS. The  necessary
       support	for  TLS  object  passivation and re-activation does not exist
       without closing the session, which defeats the purpose.

       SMTP and LMTP connection caching	 assumes  that	SASL  credentials  are
       valid  for  all	destinations that map onto the same IP address and TCP
       port.

CONFIGURATION PARAMETERS
       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_xxx configuration parameters have an lmtp_xxx "mirror" param-
       eter for the equivalent LMTP  feature.  This  document  describes  only
       those LMTP-related parameters that aren't simply "mirror" parameters.

       Changes	to  main.cf  are picked up automatically, as smtp(8) processes
       run for only a limited amount of time. Use the command "postfix reload"
       to speed up a change.

       The  text  below provides only a parameter summary. See postconf(5) for
       more details including examples.

COMPATIBILITY CONTROLS
       ignore_mx_lookup_error (no)
	      Ignore DNS MX lookups that produce no response.

       smtp_always_send_ehlo (yes)
	      Always send EHLO at the start of an SMTP session.

       smtp_never_send_ehlo (no)
	      Never send EHLO at the start of an SMTP session.

       smtp_defer_if_no_mx_address_found (no)
	      Defer mail delivery when no MX record resolves to an IP address.

       smtp_line_length_limit (990)
	      The maximal length of message header and body lines that Postfix
	      will send via SMTP.

       smtp_pix_workaround_delay_time (10s)
	      How   long   the	Postfix	 SMTP  client  pauses  before  sending
	      ".<CR><LF>"  in  order  to  work	 around	  the	PIX   firewall
	      "<CR><LF>.<CR><LF>" bug.

       smtp_pix_workaround_threshold_time (500s)
	      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.

       smtp_pix_workarounds (disable_esmtp, delay_dotcrlf)
	      A	 list  that  specifies	zero or more workarounds for CISCO PIX
	      firewall bugs.

       smtp_pix_workaround_maps (empty)
	      Lookup tables, indexed by the remote SMTP server	address,  with
	      per-destination workarounds for CISCO PIX firewall bugs.

       smtp_quote_rfc821_envelope (yes)
	      Quote  addresses	in  SMTP  MAIL	FROM  and  RCPT TO commands as
	      required by RFC 2821.

       smtp_skip_5xx_greeting (yes)
	      Skip SMTP servers that greet with a 5XX status code (go away, do
	      not try again later).

       smtp_skip_quit_response (yes)
	      Do not wait for the response to the SMTP QUIT command.

       Available in Postfix version 2.0 and earlier:

       smtp_skip_4xx_greeting (yes)
	      Skip  SMTP  servers  that greet with a 4XX status code (go away,
	      try again later).

       Available in Postfix version 2.2 and later:

       smtp_discard_ehlo_keyword_address_maps (empty)
	      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.

       smtp_discard_ehlo_keywords (empty)
	      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.

       smtp_generic_maps (empty)
	      Optional	lookup	tables	that  perform address rewriting in the
	      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:

       smtp_cname_overrides_servername (version dependent)
	      Allow  DNS  CNAME	 records  to  override the servername that the
	      Postfix SMTP client uses for logging, SASL password lookup,  TLS
	      policy decisions, or TLS certificate verification.

       Available in Postfix version 2.3 and later:

       lmtp_discard_lhlo_keyword_address_maps (empty)
	      Lookup  tables,  indexed by the remote LMTP server address, with
	      case insensitive lists of LHLO keywords  (pipelining,  starttls,
	      auth,  etc.)  that  the  LMTP  client  will  ignore  in the LHLO
	      response from a remote LMTP server.

       lmtp_discard_lhlo_keywords (empty)
	      A case insensitive list of LHLO keywords (pipelining,  starttls,
	      auth,  etc.)  that  the  LMTP  client  will  ignore  in the LHLO
	      response from a remote LMTP server.

       Available in Postfix version 2.4.4 and later:

       send_cyrus_sasl_authzid (no)
	      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:

       smtp_header_checks (empty)
	      Restricted header_checks(5) tables for the Postfix SMTP client.

       smtp_mime_header_checks (empty)
	      Restricted  mime_header_checks(5)	 tables	 for  the Postfix SMTP
	      client.

       smtp_nested_header_checks (empty)
	      Restricted nested_header_checks(5) tables for the	 Postfix  SMTP
	      client.

       smtp_body_checks (empty)
	      Restricted body_checks(5) tables for the Postfix SMTP client.

       Available in Postfix version 2.6 and later:

       tcp_windowsize (0)
	      An  optional  workaround for routers that break TCP window scal-
	      ing.

MIME PROCESSING CONTROLS
       Available in Postfix version 2.0 and later:

       disable_mime_output_conversion (no)
	      Disable the conversion of 8BITMIME format to 7BIT format.

       mime_boundary_length_limit (2048)
	      The maximal length of MIME multipart boundary strings.

       mime_nesting_limit (100)
	      The maximal recursion level that the MIME processor will handle.

EXTERNAL CONTENT INSPECTION CONTROLS
       Available in Postfix version 2.1 and later:

       smtp_send_xforward_command (no)
	      Send the non-standard XFORWARD command  when  the	 Postfix  SMTP
	      server EHLO response announces XFORWARD support.

SASL AUTHENTICATION CONTROLS
       smtp_sasl_auth_enable (no)
	      Enable SASL authentication in the Postfix SMTP client.

       smtp_sasl_password_maps (empty)
	      Optional	SMTP  client  lookup tables with one username:password
	      entry per remote hostname or  domain,  or	 sender	 address  when
	      sender-dependent authentication is enabled.

       smtp_sasl_security_options (noplaintext, noanonymous)
	      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 smtp_sasl_type.

       Available in Postfix version 2.2 and later:

       smtp_sasl_mechanism_filter (empty)
	      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:

       smtp_sender_dependent_authentication (no)
	      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.

       smtp_sasl_path (empty)
	      Implementation-specific information that the Postfix SMTP client
	      passes through  to  the  SASL  plug-in  implementation  that  is
	      selected with smtp_sasl_type.

       smtp_sasl_type (cyrus)
	      The  SASL	 plug-in  type that the Postfix SMTP client should use
	      for authentication.

       Available in Postfix version 2.5 and later:

       smtp_sasl_auth_cache_name (empty)
	      An optional table to prevent repeated SASL authentication	 fail-
	      ures  with  the  same  remote SMTP server hostname, username and
	      password.

       smtp_sasl_auth_cache_time (90d)
	      The maximal age of an smtp_sasl_auth_cache_name entry before  it
	      is removed.

       smtp_sasl_auth_soft_bounce (yes)
	      When  a remote SMTP server rejects a SASL authentication request
	      with a 535 reply code, defer mail delivery instead of  returning
	      mail as undeliverable.

STARTTLS SUPPORT CONTROLS
       Detailed	 information  about STARTTLS configuration may be found in the
       TLS_README document.

       smtp_tls_security_level (empty)
	      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.

       smtp_sasl_tls_security_options ($smtp_sasl_security_options)
	      The  SASL	 authentication security options that the Postfix SMTP
	      client uses for TLS encrypted SMTP sessions.

       smtp_starttls_timeout (300s)
	      Time limit for Postfix SMTP client  write	 and  read  operations
	      during TLS startup and shutdown handshake procedures.

       smtp_tls_CAfile (empty)
	      A	 file  containing  CA certificates of root CAs trusted to sign
	      either remote SMTP server certificates or intermediate  CA  cer-
	      tificates.

       smtp_tls_CApath (empty)
	      Directory	 with  PEM  format  certificate authority certificates
	      that the Postfix SMTP client uses to verify a remote SMTP server
	      certificate.

       smtp_tls_cert_file (empty)
	      File with the Postfix SMTP client RSA certificate in PEM format.

       smtp_tls_mandatory_ciphers (medium)
	      The  minimum  TLS cipher grade that the Postfix SMTP client will
	      use with mandatory TLS encryption.

       smtp_tls_exclude_ciphers (empty)
	      List of ciphers or cipher types to exclude from the Postfix SMTP
	      client cipher list at all TLS security levels.

       smtp_tls_mandatory_exclude_ciphers (empty)
	      Additional  list	of ciphers or cipher types to exclude from the
	      SMTP client cipher list at mandatory TLS security levels.

       smtp_tls_dcert_file (empty)
	      File with the Postfix SMTP client DSA certificate in PEM format.

       smtp_tls_dkey_file ($smtp_tls_dcert_file)
	      File with the Postfix SMTP client DSA private key in PEM format.

       smtp_tls_key_file ($smtp_tls_cert_file)
	      File with the Postfix SMTP client RSA private key in PEM format.

       smtp_tls_loglevel (0)
	      Enable additional Postfix SMTP client logging of TLS activity.

       smtp_tls_note_starttls_offer (no)
	      Log the hostname of a remote SMTP server that  offers  STARTTLS,
	      when TLS is not already enabled for that server.

       smtp_tls_policy_maps (empty)
	      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 smtp_tls_per_site parameter.

       smtp_tls_mandatory_protocols (SSLv3, TLSv1)
	      List  of SSL/TLS protocols that the Postfix SMTP client will use
	      with mandatory TLS encryption.

       smtp_tls_scert_verifydepth (9)
	      The verification depth for remote SMTP server certificates.

       smtp_tls_secure_cert_match (nexthop, dot-nexthop)
	      The server certificate  peername	verification  method  for  the
	      "secure" TLS security level.

       smtp_tls_session_cache_database (empty)
	      Name of the file containing the optional Postfix SMTP client TLS
	      session cache.

       smtp_tls_session_cache_timeout (3600s)
	      The expiration time of Postfix SMTP  client  TLS	session	 cache
	      information.

       smtp_tls_verify_cert_match (hostname)
	      The  server  certificate	peername  verification	method for the
	      "verify" TLS security level.

       tls_daemon_random_bytes (32)
	      The number of pseudo-random bytes that an	 smtp(8)  or  smtpd(8)
	      process  requests from the tlsmgr(8) server in order to seed its
	      internal pseudo random number generator (PRNG).

       tls_high_cipherlist (ALL:!EXPORT:!LOW:!MEDIUM:+RC4:@STRENGTH)
	      The OpenSSL cipherlist for "HIGH" grade ciphers.

       tls_medium_cipherlist (ALL:!EXPORT:!LOW:+RC4:@STRENGTH)
	      The OpenSSL cipherlist for "MEDIUM" or higher grade ciphers.

       tls_low_cipherlist (ALL:!EXPORT:+RC4:@STRENGTH)
	      The OpenSSL cipherlist for "LOW" or higher grade ciphers.

       tls_export_cipherlist (ALL:+RC4:@STRENGTH)
	      The OpenSSL cipherlist for "EXPORT" or higher grade ciphers.

       tls_null_cipherlist (eNULL:!aNULL)
	      The OpenSSL cipherlist for "NULL"	 grade	ciphers	 that  provide
	      authentication without encryption.

       Available in Postfix version 2.4 and later:

       smtp_sasl_tls_verified_security_options		 ($smtp_sasl_tls_secu-
       rity_options)
	      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:

       smtp_tls_fingerprint_cert_match (empty)
	      List of acceptable remote SMTP server  certificate  fingerprints
	      for   the	  "fingerprint"	 TLS  security	level  (smtp_tls_secu-
	      rity_level = fingerprint).

       smtp_tls_fingerprint_digest (md5)
	      The message digest  algorithm  used  to  construct  remote  SMTP
	      server certificate fingerprints.

       Available in Postfix version 2.6 and later:

       smtp_tls_protocols (!SSLv2)
	      List  of TLS protocols that the Postfix SMTP client will exclude
	      or include with opportunistic TLS encryption.

       smtp_tls_ciphers (export)
	      The minimum TLS cipher grade that the Postfix SMTP  client  will
	      use with opportunistic TLS encryption.

       smtp_tls_eccert_file (empty)
	      File  with the Postfix SMTP client ECDSA certificate in PEM for-
	      mat.

       smtp_tls_eckey_file ($smtp_tls_eccert_file)
	      File with the Postfix SMTP client ECDSA private key in PEM  for-
	      mat.

OBSOLETE STARTTLS CONTROLS
       The  following  configuration  parameters  exist for compatibility with
       Postfix versions before 2.3. Support for these will  be	removed	 in  a
       future release.

       smtp_use_tls (no)
	      Opportunistic  mode: use TLS when a remote SMTP server announces
	      STARTTLS support, otherwise send the mail in the clear.

       smtp_enforce_tls (no)
	      Enforcement mode: require	 that  remote  SMTP  servers  use  TLS
	      encryption, and never send mail in the clear.

       smtp_tls_enforce_peername (yes)
	      With  mandatory  TLS  encryption,	 require  that the remote SMTP
	      server hostname matches  the  information	 in  the  remote  SMTP
	      server certificate.

       smtp_tls_per_site (empty)
	      Optional	lookup	tables	with the Postfix SMTP client TLS usage
	      policy by next-hop destination and by remote SMTP	 server	 host-
	      name.

       smtp_tls_cipherlist (empty)
	      Obsolete	Postfix	 < 2.3 control for the Postfix SMTP client TLS
	      cipher list.

RESOURCE AND RATE CONTROLS
       smtp_destination_concurrency_limit	 ($default_destination_concur-
       rency_limit)
	      The  maximal  number of parallel deliveries to the same destina-
	      tion via the smtp message delivery transport.

       smtp_destination_recipient_limit ($default_destination_recipient_limit)
	      The maximal number of recipients per message for the  smtp  mes-
	      sage delivery transport.

       smtp_connect_timeout (30s)
	      The  SMTP	 client time limit for completing a TCP connection, or
	      zero (use the operating system built-in time limit).

       smtp_helo_timeout (300s)
	      The SMTP client time limit for sending the HELO or EHLO command,
	      and for receiving the initial server response.

       lmtp_lhlo_timeout (300s)
	      The LMTP client time limit for sending the LHLO command, and for
	      receiving the initial server response.

       smtp_xforward_timeout (300s)
	      The SMTP client time limit for sending the XFORWARD command, and
	      for receiving the server response.

       smtp_mail_timeout (300s)
	      The  SMTP	 client	 time limit for sending the MAIL FROM command,
	      and for receiving the server response.

       smtp_rcpt_timeout (300s)
	      The SMTP client time limit for sending the SMTP RCPT TO command,
	      and for receiving the server response.

       smtp_data_init_timeout (120s)
	      The  SMTP	 client	 time limit for sending the SMTP DATA command,
	      and for receiving the server response.

       smtp_data_xfer_timeout (180s)
	      The SMTP client time limit for sending the SMTP message content.

       smtp_data_done_timeout (600s)
	      The SMTP client time limit for sending the  SMTP	".",  and  for
	      receiving the server response.

       smtp_quit_timeout (300s)
	      The SMTP client time limit for sending the QUIT command, and for
	      receiving the server response.

       Available in Postfix version 2.1 and later:

       smtp_mx_address_limit (5)
	      The maximal number of MX (mail exchanger) IP addresses that  can
	      result from mail exchanger lookups, or zero (no limit).

       smtp_mx_session_limit (2)
	      The  maximal number of SMTP sessions per delivery request before
	      giving up or delivering to a fall-back relay host, or  zero  (no
	      limit).

       smtp_rset_timeout (20s)
	      The SMTP client time limit for sending the RSET command, and for
	      receiving the server response.

       Available in Postfix version 2.2 and earlier:

       lmtp_cache_connection (yes)
	      Keep Postfix LMTP client connections open for  up	 to  $max_idle
	      seconds.

       Available in Postfix version 2.2 and later:

       smtp_connection_cache_destinations (empty)
	      Permanently  enable  SMTP	 connection  caching for the specified
	      destinations.

       smtp_connection_cache_on_demand (yes)
	      Temporarily enable SMTP connection caching while	a  destination
	      has a high volume of mail in the active queue.

       smtp_connection_reuse_time_limit (300s)
	      The amount of time during which Postfix will use an SMTP connec-
	      tion repeatedly.

       smtp_connection_cache_time_limit (2s)
	      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:

       connection_cache_protocol_timeout (5s)
	      Time  limit for connection cache connect, send or receive opera-
	      tions.

TROUBLE SHOOTING CONTROLS
       debug_peer_level (2)
	      The increment in verbose logging level when a remote  client  or
	      server matches a pattern in the debug_peer_list parameter.

       debug_peer_list (empty)
	      Optional	list  of  remote  client or server hostname or network
	      address  patterns	 that  cause  the  verbose  logging  level  to
	      increase by the amount specified in $debug_peer_level.

       error_notice_recipient (postmaster)
	      The  recipient  of  postmaster notifications about mail delivery
	      problems that are caused by policy, resource, software or proto-
	      col errors.

       internal_mail_filter_classes (empty)
	      What categories of Postfix-generated mail are subject to before-
	      queue content inspection by non_smtpd_milters, header_checks and
	      body_checks.

       notify_classes (resource, software)
	      The list of error classes that are reported to the postmaster.

MISCELLANEOUS CONTROLS
       best_mx_transport (empty)
	      Where  the  Postfix  SMTP	 client	 should	 deliver  mail when it
	      detects a "mail loops back to myself" error condition.

       config_directory (see 'postconf -d' output)
	      The default location of the Postfix main.cf and  master.cf  con-
	      figuration files.

       daemon_timeout (18000s)
	      How  much	 time  a  Postfix  daemon process may take to handle a
	      request before it is terminated by a built-in watchdog timer.

       delay_logging_resolution_limit (2)
	      The maximal number of digits after the decimal point  when  log-
	      ging sub-second delay values.

       disable_dns_lookups (no)
	      Disable DNS lookups in the Postfix SMTP and LMTP clients.

       inet_interfaces (all)
	      The  network  interface addresses that this mail system receives
	      mail on.

       inet_protocols (ipv4)
	      The Internet protocols Postfix will attempt to use  when	making
	      or accepting connections.

       ipc_timeout (3600s)
	      The  time	 limit	for  sending  or receiving information over an
	      internal communication channel.

       lmtp_assume_final (no)
	      When an LMTP server announces no DSN support,  assume  that  the
	      server  performs	final  delivery, and send "delivered" delivery
	      status notifications instead of "relayed".

       lmtp_tcp_port (24)
	      The default TCP port that the Postfix LMTP client connects to.

       max_idle (100s)
	      The maximum amount of time that an idle Postfix  daemon  process
	      waits for an incoming connection before terminating voluntarily.

       max_use (100)
	      The maximal number of incoming connections that a Postfix daemon
	      process will service before terminating voluntarily.

       process_id (read-only)
	      The process ID of a Postfix command or daemon process.

       process_name (read-only)
	      The process name of a Postfix command or daemon process.

       proxy_interfaces (empty)
	      The network interface addresses that this mail  system  receives
	      mail on by way of a proxy or network address translation unit.

       smtp_bind_address (empty)
	      An  optional  numerical  network	address	 that the Postfix SMTP
	      client should bind to when making an IPv4 connection.

       smtp_bind_address6 (empty)
	      An optional numerical network  address  that  the	 Postfix  SMTP
	      client should bind to when making an IPv6 connection.

       smtp_helo_name ($myhostname)
	      The hostname to send in the SMTP EHLO or HELO command.

       lmtp_lhlo_name ($myhostname)
	      The hostname to send in the LMTP LHLO command.

       smtp_host_lookup (dns)
	      What  mechanisms	when the Postfix SMTP client uses to look up a
	      host's IP address.

       smtp_randomize_addresses (yes)
	      Randomize the order of equal-preference MX host addresses.

       syslog_facility (mail)
	      The syslog facility of Postfix logging.

       syslog_name (see 'postconf -d' output)
	      The mail system name that is prepended to the  process  name  in
	      syslog  records,	so  that  "smtpd" becomes, for example, "post-
	      fix/smtpd".

       Available with Postfix 2.2 and earlier:

       fallback_relay (empty)
	      Optional list of relay hosts for SMTP destinations that can't be
	      found or that are unreachable.

       Available with Postfix 2.3 and later:

       smtp_fallback_relay ($fallback_relay)
	      Optional list of relay hosts for SMTP destinations that can't be
	      found or that are unreachable.

SEE ALSO
       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
       syslogd(8), system logging

README FILES
       Use "postconf readme_directory" or "postconf html_directory" to	locate
       this information.
       SASL_README, Postfix SASL howto
       TLS_README, Postfix STARTTLS howto

LICENSE
       The Secure Mailer license must be distributed with this software.

AUTHOR(S)
       Wietse Venema
       IBM T.J. Watson Research
       P.O. Box 704
       Yorktown Heights, NY 10598, 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)