Postfix manual - smtpd(8)

    SMTPD(8)                                                 SMTPD(8)

    NAME
           smtpd - Postfix SMTP server

    SYNOPSIS
           smtpd [generic Postfix daemon options]

    DESCRIPTION
           The  SMTP  server  accepts network connection requests and
           performs zero or more SMTP  transactions  per  connection.
           Each received message is piped through the cleanup(8) dae-
           mon, and is placed into the incoming queue as  one  single
           queue  file.   For  this  mode  of  operation, the program
           expects to be run from the master(8) process manager.

           Alternatively, the SMTP server takes an  established  con-
           nection  on  standard input and deposits messages directly
           into the maildrop queue.  In  this  so-called  stand-alone
           mode,  the SMTP server can accept mail even while the mail
           system is not running.

           The SMTP server implements a variety of policies for  con-
           nection  requests, and for parameters given to HELO, ETRN,
           MAIL FROM, VRFY and RCPT TO commands.  They  are  detailed
           below and in the main.cf configuration file.

    SECURITY
           The SMTP server is moderately security-sensitive. It talks
           to SMTP clients and to DNS servers  on  the  network.  The
           SMTP server can be run chrooted at fixed low privilege.

    STANDARDS
           RFC 821 (SMTP protocol)
           RFC 1123 (Host requirements)
           RFC 1652 (8bit-MIME transport)
           RFC 1869 (SMTP service extensions)
           RFC 1870 (Message Size Declaration)
           RFC 1985 (ETRN command)
           RFC 2554 (AUTH command)
           RFC 2821 (SMTP protocol)
           RFC 2920 (SMTP Pipelining)

    DIAGNOSTICS
           Problems and transactions are logged to syslogd(8).

           Depending  on the setting of the notify_classes parameter,
           the postmaster is notified of bounces, protocol  problems,
           policy violations, and of other trouble.

    CONFIGURATION PARAMETERS
           Changes   to  main.cf  are  picked  up  automatically,  as
           smtpd(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
           The following parameters work around implementation errors
           in  other software, and/or allow you to override standards
           in order to prevent undesirable use.

           broken_sasl_auth_clients (no)
                  Enable inter-operability  with  SMTP  clients  that
                  implement  an  obsolete version of the AUTH command
                  (RFC 2554).

           disable_vrfy_command (no)
                  Disable the SMTP VRFY command.

           smtpd_noop_commands (empty)
                  List of  commands  that  the  Postfix  SMTP  server
                  replies  to with "250 Ok", without doing any syntax
                  checks and without changing state.

           strict_rfc821_envelopes (no)
                  Require that addresses received in SMTP  MAIL  FROM
                  and RCPT TO commands are enclosed with <>, and that
                  those addresses do not contain RFC 822  style  com-
                  ments or phrases.

           Available in Postfix version 2.1 and later:

           resolve_null_domain (no)
                  Resolve an address that ends in the "@" null domain
                  as if the local hostname were specified, instead of
                  rejecting the address as invalid.

           smtpd_reject_unlisted_sender (no)
                  Request  that  the Postfix SMTP server rejects mail
                  from  unknown  sender  addresses,  even   when   no
                  explicit  reject_unlisted_sender access restriction
                  is specified.

           smtpd_sasl_exceptions_networks (empty)
                  What SMTP clients Postfix will not offer AUTH  sup-
                  port to.

    AFTER QUEUE EXTERNAL CONTENT INSPECTION CONTROLS
           As  of  version 1.0, Postfix can be configured to send new
           mail to an external  content  filter  AFTER  the  mail  is
           queued.  This  content  filter  is expected to inject mail
           back into a (Postfix or other) MTA for  further  delivery.
           See the FILTER_README document for details.

           content_filter (empty)
                  The  name of a mail delivery transport that filters
                  mail after it is queued.

    BEFORE QUEUE EXTERNAL CONTENT INSPECTION CONTROLS
           As of version 2.1, the Postfix SMTP server can be  config-
           ured  to send incoming mail to a real-time SMTP-based con-
           tent filter BEFORE mail is queued.  This content filter is
           expected  to  inject  mail  back  into  Postfix.   See the
           SMTPD_PROXY_README document for details on how to  config-
           ure and operate this feature.

           smtpd_proxy_filter (empty)
                  The  hostname  and  TCP  port of the mail filtering
                  proxy server.

           smtpd_proxy_ehlo ($myhostname)
                  How the Postfix SMTP server announces itself to the
                  proxy filter.

           smtpd_proxy_timeout (100s)
                  The time limit for connecting to a proxy filter and
                  for sending or receiving information.

    GENERAL CONTENT INSPECTION CONTROLS
           The following parameters are applicable for both  built-in
           and external content filters.

           Available in Postfix version 2.1 and later:

           receive_override_options (empty)
                  Enable  or  disable  recipient validation, built-in
                  content filtering, or address rewriting.

    EXTERNAL CONTENT INSPECTION CONTROLS
           The following parameters are applicable for  both  before-
           queue and after-queue content filtering.

           Available in Postfix version 2.1 and later:

           smtpd_authorized_xforward_hosts (empty)
                  What  SMTP  clients are allowed to use the XFORWARD
                  feature.

    SASL AUTHENTICATION CONTROLS
           Postfix SASL support (RFC 2554) can be used  to  authenti-
           cate  remote  SMTP clients to the Postfix SMTP server, and
           to authenticate the Postfix SMTP client to a  remote  SMTP
           server.  See the SASL_README document for details.

           broken_sasl_auth_clients (no)
                  Enable  inter-operability  with  SMTP  clients that
                  implement an obsolete version of the  AUTH  command
                  (RFC 2554).

           smtpd_sasl_auth_enable (no)
                  Enable  SASL  authentication  in  the  Postfix SMTP
                  server.

           smtpd_sasl_application_name (smtpd)
                  The application name used for SASL server  initial-
                  ization.

           smtpd_sasl_local_domain (empty)
                  The name of the local SASL authentication realm.

           smtpd_sasl_security_options (noanonymous)
                  Restrict what authentication mechanisms the Postfix
                  SMTP server will offer to the client.

           smtpd_sender_login_maps (empty)
                  Optional lookup table with  the  SASL  login  names
                  that own sender (MAIL FROM) addresses.

           Available in Postfix version 2.1 and later:

           smtpd_sasl_exceptions_networks (empty)
                  What  SMTP clients Postfix will not offer AUTH sup-
                  port to.

    VERP SUPPORT CONTROLS
           With VERP style delivery,  each  recipient  of  a  message
           receives a customized copy of the message with his/her own
           recipient address encoded in the envelope sender  address.
           The VERP_README file describes configuration and operation
           details of Postfix support for  variable  envelope  return
           path addresses.  VERP style delivery is requested with the
           SMTP XVERP command or with the "sendmail -V"  command-line
           option  and is available in Postfix version 1.1 and later.

           default_verp_delimiters (+=)
                  The two default VERP delimiter characters.

           verp_delimiter_filter (-=+)
                  The characters Postfix accepts  as  VERP  delimiter
                  characters  on the Postfix sendmail(1) command line
                  and in SMTP commands.

           Available in Postfix version 1.1 and 2.0:

           authorized_verp_clients ($mynetworks)
                  What SMTP clients are allowed to specify the  XVERP
                  command.

           Available in Postfix version 2.1 and later:

           smtpd_authorized_verp_clients ($authorized_verp_clients)
                  What  SMTP clients are allowed to specify the XVERP
                  command.

    TROUBLE SHOOTING CONTROLS
           The DEBUG_README document describes how to debug parts  of
           the  Postfix mail system. The methods vary from making the
           software log a lot of detail, to running some daemon  pro-
           cesses under control of a call tracer or debugger.

           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 protocol errors.

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

           soft_bounce (no)
                  Safety net to keep mail queued that would otherwise
                  be returned to the sender.

           Available in Postfix version 2.1 and later:

           smtpd_authorized_xclient_hosts (empty)
                  What SMTP clients are allowed to  use  the  XCLIENT
                  feature.

    KNOWN VERSUS UNKNOWN RECIPIENT CONTROLS
           As  of  Postfix  version 2.0, the SMTP server rejects mail
           for unknown recipients. This prevents the mail queue  from
           clogging  up  with  undeliverable  MAILER-DAEMON messages.
           Additional  information  on   this   topic   is   in   the
           LOCAL_RECIPIENT_README and ADDRESS_CLASS_README documents.

           show_user_unknown_table_name (yes)
                  Display the name of  the  recipient  table  in  the
                  "User unknown" responses.

           canonical_maps (empty)
                  Optional  address mapping lookup tables for message
                  headers and envelopes.

           recipient_canonical_maps (empty)
                  Optional address mapping lookup tables for envelope
                  and header recipient addresses.

           Parameters concerning known/unknown local recipients:

           mydestination  ($myhostname,  localhost.$mydomain,  local-
           host)
                  The  list  of  domains  that  are delivered via the
                  $local_transport mail delivery transport.

           inet_interfaces (all)
                  The network interface addresses that this mail sys-
                  tem receives mail on.

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

           local_recipient_maps             (proxy:unix:passwd.byname
           $alias_maps)
                  Lookup  tables with all names or addresses of local
                  recipients: a recipient address is local  when  its
                  domain  matches $mydestination, $inet_interfaces or
                  $proxy_interfaces.

           unknown_local_recipient_reject_code (550)
                  The numerical Postfix  SMTP  server  response  code
                  when    a   recipient   address   is   local,   and
                  $local_recipient_maps specifies a  list  of  lookup
                  tables that does not match the recipient.

           Parameters  concerning  known/unknown  recipients of relay
           destinations:

           relay_domains ($mydestination)
                  What destination domains (and  subdomains  thereof)
                  this system will relay mail to.

           relay_recipient_maps (empty)
                  Optional  lookup tables with all valid addresses in
                  the domains that match $relay_domains.

           unknown_relay_recipient_reject_code (550)
                  The numerical Postfix SMTP server reply code when a
                  recipient   address   matches  $relay_domains,  and
                  relay_recipient_maps specifies  a  list  of  lookup
                  tables that does not match the recipient address.

           Parameters  concerning known/unknown recipients in virtual
           alias domains:

           virtual_alias_domains ($virtual_alias_maps)
                  Optional list of names of  virtual  alias  domains,
                  that  is,  domains  for  which  all  addresses  are
                  aliased to  addresses  in  other  local  or  remote
                  domains.

           virtual_alias_maps ($virtual_maps)
                  Optional  lookup  tables  that  alias specific mail
                  addresses or  domains  to  other  local  or  remote
                  address.

           unknown_virtual_alias_reject_code (550)
                  The SMTP server reply code when a recipient address
                  matches    $virtual_alias_domains,    and     $vir-
                  tual_alias_maps  specifies  a list of lookup tables
                  that does not match the recipient address.

           Parameters concerning known/unknown recipients in  virtual
           mailbox domains:

           virtual_mailbox_domains ($virtual_mailbox_maps)
                  The  list  of  domains  that  are delivered via the
                  $virtual_transport mail delivery transport.

           virtual_mailbox_maps (empty)
                  Optional lookup tables with all valid addresses  in
                  the domains that match $virtual_mailbox_domains.

           unknown_virtual_mailbox_reject_code (550)
                  The SMTP server reply code when a recipient address
                  matches   $virtual_mailbox_domains,    and    $vir-
                  tual_mailbox_maps specifies a list of lookup tables
                  that does not match the recipient address.

    RESOURCE AND RATE CONTROLS
           The following parameters limit resource usage by the  SMTP
           server and/or control client request rates.

           line_length_limit (2048)
                  Upon  input,  long lines are chopped up into pieces
                  of at most this length; upon delivery,  long  lines
                  are reconstructed.

           queue_minfree (0)
                  The  minimal  amount  of free space in bytes in the
                  queue file system that is needed to receive mail.

           message_size_limit (10240000)
                  The maximal size in bytes of a  message,  including
                  envelope information.

           smtpd_recipient_limit (1000)
                  The  maximal  number of recipients that the Postfix
                  SMTP server accepts per message delivery request.

           smtpd_timeout (300s)
                  The time limit for sending a  Postfix  SMTP  server
                  response  and  for  receiving  a remote SMTP client
                  request.

           smtpd_history_flush_threshold (100)
                  The maximal number of lines  in  the  Postfix  SMTP
                  server  command  history  before it is flushed upon
                  receipt of EHLO, RSET, or end of DATA.

           Not available in Postfix version 2.1:

           smtpd_client_connection_count_limit (50)
                  How many simultaneous connections any  SMTP  client
                  is allowed to make to the SMTP service.

           smtpd_client_connection_rate_limit (0)
                  The  maximal  number  of  connection  attempts  any
                  client is allowed to make to this service per  time
                  unit.

           smtpd_client_connection_limit_exceptions ($mynetworks)
                  Clients  that are excluded from connection count or
                  connection rate restrictions.

    TARPIT CONTROLS
           When a remote SMTP client makes errors, the  Postfix  SMTP
           server  can insert delays before responding. This can help
           to slow down run-away  software.   The  behavior  is  con-
           trolled  by  an  error  counter  that counts the number of
           errors within an SMTP session that a client makes  without
           delivering mail.

           smtpd_error_sleep_time (1s)
                  With   Postfix  2.1  and  later:  the  SMTP  server
                  response delay after a client has  made  more  than
                  $smtpd_soft_error_limit   errors,  and  fewer  than
                  $smtpd_hard_error_limit errors, without  delivering
                  mail.

           smtpd_soft_error_limit (10)
                  The  number  of  errors  a  remote  SMTP  client is
                  allowed to make without delivering mail before  the
                  Postfix SMTP server slows down all its responses.

           smtpd_hard_error_limit (20)
                  The  maximal  number of errors a remote SMTP client
                  is allowed to make without delivering mail.

           smtpd_junk_command_limit (100)
                  The number of junk commands (NOOP,  VRFY,  ETRN  or
                  RSET) that a remote SMTP client can send before the
                  Postfix SMTP server starts to increment  the  error
                  counter with each junk command.

           Available in Postfix version 2.1 and later:

           smtpd_recipient_overshoot_limit (1000)
                  The  number of recipients that a remote SMTP client
                  can send in excess  of  the  limit  specified  with
                  $smtpd_recipient_limit,  before  the  Postfix  SMTP
                  server increments the per-session error  count  for
                  each excess recipient.

    ACCESS POLICY DELEGATION CONTROLS
           As  of  version 2.1, Postfix can be configured to delegate
           access policy decisions to an external  server  that  runs
           outside  Postfix.   See  the  file SMTPD_POLICY_README for
           more information.

           smtpd_policy_service_max_idle (300s)
                  The time after which an idle SMTPD  policy  service
                  connection is closed.

           smtpd_policy_service_max_ttl (1000s)
                  The time after which an active SMTPD policy service
                  connection is closed.

           smtpd_policy_service_timeout (100s)
                  The time limit for connecting  to,  writing  to  or
                  receiving from a delegated SMTPD policy server.

    ACCESS CONTROLS
           The  SMTPD_ACCESS_README document gives an introduction to
           all the SMTP server access control features.

           smtpd_delay_reject (yes)
                  Wait until the RCPT TO  command  before  evaluating
                  $smtpd_client_restrictions,    $smtpd_helo_restric-
                  tions and $smtpd_sender_restrictions, or wait until
                  the      ETRN     command     before     evaluating
                  $smtpd_client_restrictions and $smtpd_helo_restric-
                  tions.

           parent_domain_matches_subdomains  (see  'postconf -d' out-
           put)
                  What   Postfix   features   match   subdomains   of
                  "domain.tld" automatically, instead of requiring an
                  explicit ".domain.tld" pattern.

           smtpd_client_restrictions (empty)
                  Optional  SMTP  server  access  restrictions in the
                  context of a client SMTP connection request.

           smtpd_helo_required (no)
                  Require that a remote SMTP client introduces itself
                  at  the  beginning of an SMTP session with the HELO
                  or EHLO command.

           smtpd_helo_restrictions (empty)
                  Optional restrictions that the Postfix SMTP  server
                  applies in the context of the SMTP HELO command.

           smtpd_sender_restrictions (empty)
                  Optional  restrictions that the Postfix SMTP server
                  applies in the context of the MAIL FROM command.

           smtpd_recipient_restrictions           (permit_mynetworks,
           reject_unauth_destination)
                  The  access  restrictions  that  the  Postfix  SMTP
                  server  applies  in the context of the RCPT TO com-
                  mand.

           smtpd_etrn_restrictions (empty)
                  Optional SMTP server  access  restrictions  in  the
                  context of a client ETRN request.

           allow_untrusted_routing (no)
                  Forward    mail   with   sender-specified   routing
                  (user[@%!]remote[@%!]site) from  untrusted  clients
                  to destinations matching $relay_domains.

           smtpd_restriction_classes (empty)
                  User-defined  aliases for groups of access restric-
                  tions.

           smtpd_null_access_lookup_key (<>)
                  The lookup key to be used in SMTP access(5)  tables
                  instead of the null sender address.

           permit_mx_backup_networks (empty)
                  Restrict  the  use  of  the  permit_mx_backup  SMTP
                  access feature to only  domains  whose  primary  MX
                  hosts match the listed networks.

           Available in Postfix version 2.0 and later:

           smtpd_data_restrictions (empty)
                  Optional  access restrictions that the Postfix SMTP
                  server applies in the context of the SMTP DATA com-
                  mand.

           smtpd_expansion_filter (see 'postconf -d' output)
                  What  characters are allowed in $name expansions of
                  RBL reply templates.

           Available in Postfix version 2.1 and later:

           smtpd_reject_unlisted_sender (no)
                  Request that the Postfix SMTP server  rejects  mail
                  from   unknown   sender  addresses,  even  when  no
                  explicit reject_unlisted_sender access  restriction
                  is specified.

           smtpd_reject_unlisted_recipient (yes)
                  Request  that  the Postfix SMTP server rejects mail
                  for  unknown  recipient  addresses,  even  when  no
                  explicit  reject_unlisted_recipient access restric-
                  tion is specified.

    SENDER AND RECIPIENT ADDRESS VERIFICATION CONTROLS
           Postfix  version  2.1  introduces  sender  and   recipient
           address  verification.   This  feature  is  implemented by
           sending probe email messages that are not actually  deliv-
           ered.   This  feature  is requested via the reject_unveri-
           fied_sender   and    reject_unverified_recipient    access
           restrictions.   The status of verification probes is main-
           tained by the verify(8) server.  See the file ADDRESS_VER-
           IFICATION_README  for  information  about how to configure
           and operate the Postfix sender/recipient address verifica-
           tion service.

           address_verify_poll_count (3)
                  How  many  times to query the verify(8) service for
                  the completion of an address  verification  request
                  in progress.

           address_verify_poll_delay (3s)
                  The  delay between queries for the completion of an
                  address verification request in progress.

           address_verify_sender (postmaster)
                  The sender address to use in  address  verification
                  probes.

           unverified_sender_reject_code (450)
                  The  numerical  Postfix  SMTP  server response code
                  when  a  recipient  address  is  rejected  by   the
                  reject_unverified_sender restriction.

           unverified_recipient_reject_code (450)
                  The  numerical  Postfix SMTP server response when a
                  recipient address is rejected by the reject_unveri-
                  fied_recipient restriction.

    ACCESS CONTROL RESPONSES
           The  following  parameters  control  numerical  SMTP reply
           codes and/or text responses.

           access_map_reject_code (554)
                  The numerical Postfix  SMTP  server  response  code
                  when  a  client  is  rejected  by  an access(5) map
                  restriction.

           defer_code (450)
                  The numerical Postfix  SMTP  server  response  code
                  when  a  remote  SMTP client request is rejected by
                  the "defer" restriction.

           invalid_hostname_reject_code (501)
                  The numerical Postfix  SMTP  server  response  code
                  when  the  client HELO or EHLO command parameter is
                  rejected by  the  reject_invalid_hostname  restric-
                  tion.

           maps_rbl_reject_code (554)
                  The  numerical  Postfix  SMTP  server response code
                  when a remote SMTP client request is blocked by the
                  reject_rbl_client,             reject_rhsbl_client,
                  reject_rhsbl_sender    or    reject_rhsbl_recipient
                  restriction.

           non_fqdn_reject_code (504)
                  The numerical Postfix SMTP server reply code when a
                  client    request    is     rejected     by     the
                  reject_non_fqdn_hostname, reject_non_fqdn_sender or
                  reject_non_fqdn_recipient restriction.

           reject_code (554)
                  The numerical Postfix  SMTP  server  response  code
                  when  a  remote  SMTP client request is rejected by
                  the "reject" restriction.

           relay_domains_reject_code (554)
                  The numerical Postfix  SMTP  server  response  code
                  when   a   client   request   is  rejected  by  the
                  reject_unauth_destination recipient restriction.

           unknown_address_reject_code (450)
                  The numerical Postfix  SMTP  server  response  code
                  when  a  sender or recipient address is rejected by
                  the         reject_unknown_sender_domain         or
                  reject_unknown_recipient_domain restriction.

           unknown_client_reject_code (450)
                  The  numerical  Postfix  SMTP  server response code
                  when a client without valid address <=>  name  map-
                  ping   is  rejected  by  the  reject_unknown_client
                  restriction.

           unknown_hostname_reject_code (450)
                  The numerical Postfix  SMTP  server  response  code
                  when  the  hostname specified with the HELO or EHLO
                  command is rejected by the  reject_unknown_hostname
                  restriction.

           Available in Postfix version 2.0 and later:

           default_rbl_reply (see 'postconf -d' output)
                  The  default  SMTP  server  response template for a
                  request that is rejected by an  RBL-based  restric-
                  tion.

           multi_recipient_bounce_reject_code (550)
                  The  numerical  Postfix  SMTP  server response code
                  when a remote SMTP client request is blocked by the
                  reject_multi_recipient_bounce restriction.

           rbl_reply_maps (empty)
                  Optional lookup tables with RBL response templates.

    MISCELLANEOUS CONTROLS
           config_directory (see 'postconf -d' output)
                  The default location of  the  Postfix  main.cf  and
                  master.cf configuration 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.

           command_directory (see 'postconf -d' output)
                  The  location  of  all  postfix administrative com-
                  mands.

           double_bounce_sender (double-bounce)
                  The sender address of postmaster notifications that
                  are generated by the mail system.

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

           mail_name (Postfix)
                  The mail system name that is displayed in Received:
                  headers,  in  the  SMTP  greeting  banner,  and  in
                  bounced mail.

           mail_owner (postfix)
                  The UNIX system account that owns the Postfix queue
                  and most Postfix daemon processes.

           max_idle (100s)
                  The  maximum  amount  of  time that an idle Postfix
                  daemon process waits for the next  service  request
                  before exiting.

           max_use (100)
                  The  maximal number of connection requests before a
                  Postfix daemon process terminates.

           myhostname (see 'postconf -d' output)
                  The internet hostname of this mail system.

           mynetworks (see 'postconf -d' output)
                  The list of "trusted" SMTP clients that  have  more
                  privileges than "strangers".

           myorigin ($myhostname)
                  The domain name that locally-posted mail appears to
                  come from, and that locally posted mail  is  deliv-
                  ered to.

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

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

           queue_directory (see 'postconf -d' output)
                  The  location of the Postfix top-level queue direc-
                  tory.

           recipient_delimiter (empty)
                  The separator between user names and address exten-
                  sions (user+foo).

           smtpd_banner ($myhostname ESMTP $mail_name)
                  The  text  that  follows the 220 status code in the
                  SMTP greeting banner.

           syslog_facility (mail)
                  The syslog facility of Postfix logging.

           syslog_name (postfix)
                  The mail system name that is prepended to the  pro-
                  cess  name  in  syslog  records,  so  that  "smtpd"
                  becomes, for example, "postfix/smtpd".

    SEE ALSO
           cleanup(8), message canonicalization
           trivial-rewrite(8), address resolver
           verify(8), address verification service
           postconf(5), configuration parameters
           master(8), process manager
           syslogd(8), system logging

    README FILES
           ADDRESS_CLASS_README, blocking unknown hosted or relay recipients
           FILTER_README, external after-queue content filter
           LOCAL_RECIPIENT_README, blocking unknown local recipients
           SMTPD_ACCESS_README, built-in access policies
           SMTPD_POLICY_README, external policy server
           SMTPD_PROXY_README, external before-queue content filter
           SASL_README, Postfix SASL howto
           VERP_README, Postfix XVERP extension
           XCLIENT_README, Postfix XCLIENT extension
           XFORWARD_README, Postfix XFORWARD extension

    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

                                                             SMTPD(8)