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, 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 1651 (SMTP service extensions)
       RFC 1652 (8bit-MIME transport)
       RFC 1854 (SMTP Pipelining)
       RFC 1870 (Message Size Declaration)
       RFC 1985 (ETRN command) (partial)
       RFC 2554 (AUTH command)

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.

BUGS
       RFC  1985  is  implemented  by  forcing  delivery  of  all
       deferred mail.

CONFIGURATION PARAMETERS
       The following main.cf parameters are  especially  relevant
       to  this  program. See the Postfix main.cf file for syntax



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SMTPD(8)                                                 SMTPD(8)


       details and for default values.  Use  the  postfix  reload
       command after a configuration change.

Compatibility controls
       strict_rfc821_envelopes
              Disallow  non-RFC 821 style addresses in envelopes.
              For example, allow RFC822-style address forms  with
              comments, like Sendmail does.

Content inspection controls
       content_filter
              The  name of a mail delivery transport that filters
              mail and that either bounces mail or re-injects the
              result  back into Postfix.  This parameter uses the
              same syntax as the right-hand  side  of  a  Postfix
              transport table.

Authenication controls
       enable_sasl_authentication
              Enable  per-session  authentication as per RFC 2554
              (SASL).  This functionality is available only  when
              explicitly  selected  at  program  build  time  and
              explicitly enabled at runtime.

       smtpd_sasl_security_options
              Zero or more of the following.

              noplaintext
                     Disallow  authentication  methods  that  use
                     plaintext passwords.

              noactive
                     Disallow  authentication  methods  that  are
                     vulnerable to non-dictionary active attacks.

              nodictionary
                     Disallow  authentication  methods  that  are
                     vulnerable to passive dictionary attack.

              noanonymous
                     Disallow anonymous logins.

Miscellaneous
       always_bcc
              Address to send a copy of each message that  enters
              the system.

       command_directory
              Location  of  Postfix  support  commands  (default:
              $program_directory).

       debug_peer_level
              Increment in verbose logging level  when  a  remote
              host  matches  a  pattern  in  the  debug_peer_list



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SMTPD(8)                                                 SMTPD(8)


              parameter.

       debug_peer_list
              List of domain or network patterns. When  a  remote
              host  matches  a pattern, increase the verbose log-
              ging  level  by  the  amount   specified   in   the
              debug_peer_level parameter.

       error_notice_recipient
              Recipient    of   protocol/policy/resource/software
              error notices.

       hopcount_limit
              Limit the number of Received: message headers.

       local_recipient_maps
              List of maps with user  names  that  are  local  to
              $myorigin or $inet_interfaces. If this parameter is
              defined, then the  SMTP  server  rejects  mail  for
              unknown local users.

       notify_classes
              List of error classes. Of special interest are:

              policy When  a  client  violates any policy, mail a
                     transcript of the entire SMTP session to the
                     postmaster.

              protocol
                     When  a client violates the SMTP protocol or
                     issues  an  unimplemented  command,  mail  a
                     transcript of the entire SMTP session to the
                     postmaster.

       smtpd_banner
              Text that follows the 220 status code in  the  SMTP
              greeting banner.

       smtpd_recipient_limit
              Restrict  the  number  of  recipients that the SMTP
              server accepts per message delivery.

       smtpd_timeout
              Limit the time to send a  server  response  and  to
              receive a client request.

Resource controls
       line_length_limit
              Limit  the  amount  of memory in bytes used for the
              handling of partial input lines.

       message_size_limit
              Limit the total size in bytes of a message, includ-
              ing on-disk storage for envelope information.



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SMTPD(8)                                                 SMTPD(8)


       queue_minfree
              Minimal  amount of free space in bytes in the queue
              file system for the SMTP server to accept any  mail
              at all.

Tarpitting
       smtpd_error_sleep_time
              Time to wait in seconds before sending a 4xx or 5xx
              server error response.

       smtpd_soft_error_limit
              When an SMTP client has made this number of errors,
              wait  error_count  seconds before responding to any
              client request.

       smtpd_hard_error_limit
              Disconnect after a client has made this  number  of
              errors.

       smtpd_junk_command_limit
              Limit the number of times a client can issue a junk
              command such as NOOP, VRFY, ETRN  or  RSET  in  one
              SMTP  session  before  it  is penalized with tarpit
              delays.

UCE control restrictions
       smtpd_client_restrictions
              Restrict what clients may connect to this mail sys-
              tem.

       smtpd_helo_required
              Require  that  clients  introduce themselves at the
              beginning of an SMTP session.

       smtpd_helo_restrictions
              Restrict what client hostnames are allowed in  HELO
              and EHLO commands.

       smtpd_sender_restrictions
              Restrict  what sender addresses are allowed in MAIL
              FROM commands.

       smtpd_recipient_restrictions
              Restrict what recipient addresses  are  allowed  in
              RCPT TO commands.

       smtpd_etrn_restrictions
              Restrict what domain names can be used in ETRN com-
              mands, and what clients may issue ETRN commands.

       allow_untrusted_routing
              Allow untrusted clients to specify  addresses  with
              sender-specified  routing.   Enabling this opens up
              nasty relay loopholes involving trusted  backup  MX



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SMTPD(8)                                                 SMTPD(8)


              hosts.

       restriction_classes
              Declares  the  name of zero or more parameters that
              contain a list of UCE restrictions.  The  names  of
              these  parameters  can  then be used instead of the
              restriction lists that they represent.

       maps_rbl_domains
              List of DNS domains that publish the  addresses  of
              blacklisted hosts.

       relay_domains
              Restrict  what domains or networks this mail system
              will relay mail from or to.

UCE control responses
       access_map_reject_code
              Server response when a client  violates  an  access
              database restriction.

       invalid_hostname_reject_code
              Server   response   when   a  client  violates  the
              reject_invalid_hostname restriction.

       maps_rbl_reject_code
              Server  response  when  a   client   violates   the
              maps_rbl_domains restriction.

       reject_code
              Response  code  when  the  client  matches a reject
              restriction.

       relay_domains_reject_code
              Server response when a client attempts  to  violate
              the mail relay policy.

       unknown_address_reject_code
              Server   response   when   a  client  violates  the
              reject_unknown_address restriction.

       unknown_client_reject_code
              Server response when a client  without  address  to
              name  mapping  violates  the reject_unknown_clients
              restriction.

       unknown_hostname_reject_code
              Server  response  when  a   client   violates   the
              reject_unknown_hostname restriction.

SEE ALSO
       cleanup(8) message canonicalization
       master(8) process manager
       syslogd(8) system logging



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SMTPD(8)                                                 SMTPD(8)


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
















































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