Postfix manual - cleanup(8)

    CLEANUP(8)                                                          CLEANUP(8)

    NAME
           cleanup - canonicalize and enqueue Postfix message

    SYNOPSIS
           cleanup [generic Postfix daemon options]

    DESCRIPTION
           The  cleanup(8)  daemon  processes  inbound  mail,  inserts it into the
           incoming mail queue, and informs the queue manager of its arrival.

           The cleanup(8) daemon performs the following transformations:

           o      Insert missing  message  headers:  (Resent-)  From:,  To:,  Mes-
                  sage-Id:, and Date:.
                  This   is  enabled  with  the  local_header_rewrite_clients  and
                  always_add_missing_headers parameter settings.

           o      Transform  envelope  and  header  addresses  to   the   standard
                  user@fully-qualified-domain form that is expected by other Post-
                  fix programs.  This task depends on the trivial-rewrite(8)  dae-
                  mon.
                  The  header  transformation is enabled with the local_header_re-
                  write_clients parameter setting.

           o      Eliminate duplicate envelope recipient addresses.
                  This is enabled with the duplicate_filter_limit  parameter  set-
                  ting.

           o      Remove   message   headers:   Bcc,  Content-Length,  Resent-Bcc,
                  Return-Path.
                  This is enabled with the message_drop_headers parameter setting.

           o      Optionally,  rewrite all envelope and header addresses according
                  to the mappings specified in the canonical(5) lookup tables.
                  The header transformation is enabled with  the  local_header_re-
                  write_clients parameter setting.

           o      Optionally,  masquerade  envelope  sender  addresses and message
                  header addresses (i.e. strip host or  domain  information  below
                  all  domains  listed in the masquerade_domains parameter, except
                  for user names listed in  masquerade_exceptions).   By  default,
                  address masquerading does not affect envelope recipients.
                  The  header  transformation is enabled with the local_header_re-
                  write_clients parameter setting.

           o      Optionally, expand envelope recipients according to  information
                  found in the virtual_alias_maps lookup tables.

           The  cleanup(8)  daemon  performs  sanity checks on the content of each
           message. When it finds a problem, by default it  returns  a  diagnostic
           status to the cleanup service client, and leaves it up to the client to
           deal with the  problem.  Alternatively,  the  client  can  request  the
           cleanup(8)  daemon  to bounce the message back to the sender in case of
           trouble.

    STANDARDS
           RFC 822 (ARPA Internet Text Messages)
           RFC 2045 (MIME: Format of Internet Message Bodies)
           RFC 2046 (MIME: Media Types)
           RFC 2822 (Internet Message Format)
           RFC 3463 (Enhanced Status Codes)
           RFC 3464 (Delivery status notifications)
           RFC 5322 (Internet Message Format)
           RFC 8689 (TLS-Required: message header)

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

    BUGS
           Table-driven rewriting rules make it hard to express if then  else  and
           other logical relationships.

    CONFIGURATION PARAMETERS
           Changes to main.cf are picked up automatically, as cleanup(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
           undisclosed_recipients_header (see 'postconf -d' output)
                  Message header that the Postfix cleanup(8) server inserts when a
                  message contains no To: or Cc: message header.

           Available in Postfix version 2.1 only:

           enable_errors_to (no)
                  Report  mail  delivery  errors to the address specified with the
                  non-standard Errors-To: message header, instead of the  envelope
                  sender  address  (this  feature  is removed with Postfix version
                  2.2, is turned off by default with Postfix version 2.1,  and  is
                  always turned on with older Postfix versions).

           Available in Postfix version 2.6 and later:

           always_add_missing_headers (no)
                  Always  add  (Resent-)  From:, To:, Date: or Message-ID: headers
                  when not present.

           Available in Postfix version 2.9 and later:

           enable_long_queue_ids (no)
                  Enable long, non-repeating, queue IDs (queue file names).

    HEADER FORMATTING CONTROLS
           Available in Postfix version 3.0 and later:

           message_drop_headers (bcc, content-length, resent-bcc, return-path)
                  Names of message headers that the cleanup(8) daemon will  remove
                  after  applying  header_checks(5)  and  before  invoking  Milter
                  applications.

           Available in Postfix version 3.3 and later:

           header_from_format (standard)
                  The format of the Postfix-generated From: header.

           Available in Postfix version 3.10 and later:

           full_name_encoding_charset (utf-8)
                  The character set name (also called "charset") that Postfix will
                  output  when it automatically generates an RFC 2047 encoded full
                  name.

           non_empty_end_of_header_action (fix_quietly)
                  How the cleanup(8) daemon will process a message when  the  pri-
                  mary message header is terminated with a non-empty line.

    BUILT-IN CONTENT FILTERING CONTROLS
           Postfix built-in content filtering is meant to stop a flood of worms or
           viruses. It is not a general content filter.

           body_checks (empty)
                  Optional lookup tables for content inspection  as  specified  in
                  the body_checks(5) manual page.

           header_checks (empty)
                  Optional   lookup  tables  for  content  inspection  of  primary
                  non-MIME message headers, as specified in  the  header_checks(5)
                  manual page.

           Available in Postfix version 2.0 and later:

           body_checks_size_limit (51200)
                  How  much  text in a message body segment (or attachment, if you
                  prefer to use that term) is subjected to body_checks inspection.

           mime_header_checks ($header_checks)
                  Optional  lookup  tables  for content inspection of MIME related
                  message headers, as described  in  the  header_checks(5)  manual
                  page.

           nested_header_checks ($header_checks)
                  Optional  lookup  tables for content inspection of non-MIME mes-
                  sage  headers  in  attached  messages,  as  described   in   the
                  header_checks(5) manual page.

           Available in Postfix version 2.3 and later:

           message_reject_characters (empty)
                  The  set  of characters that Postfix will reject in message con-
                  tent.

           message_strip_characters (empty)
                  The set of characters that Postfix will remove from message con-
                  tent.

           Available  in  Postfix  version 3.9, 3.8.5, 3.7.10, 3.6.14, 3.5.24, and
           later:

           cleanup_replace_stray_cr_lf (yes)
                  Replace each stray <CR> or <LF>  character  in  message  content
                  with  a space character, to prevent outbound SMTP smuggling, and
                  to make the evaluation of Postfix-added DKIM or other signatures
                  independent  from  how a remote mail server handles such charac-
                  ters.

    BEFORE QUEUE MILTER CONTROLS
           As of version 2.3, Postfix supports the Sendmail version 8 Milter (mail
           filter)  protocol.  When  mail is not received via the smtpd(8) server,
           the cleanup(8) server will simulate SMTP events to the extent that this
           is possible. For details see the MILTER_README document.

           non_smtpd_milters (empty)
                  A  list  of  Milter (mail filter) applications for new mail that
                  does not arrive via the Postfix smtpd(8) server.

           milter_protocol (6)
                  The mail filter protocol version and  optional  protocol  exten-
                  sions  for  communication  with  a  Milter application; prior to
                  Postfix 2.6 the default protocol is 2.

           milter_default_action (Postfix >= 3.11: shutdown; Postfix < 3.11: temp-
           fail)
                  The default action when  a  Milter  (mail  filter)  response  is
                  unavailable  (for  example,  bad Postfix configuration or Milter
                  failure).

           milter_macro_daemon_name ($myhostname)
                  The {daemon_name} macro value for Milter (mail filter)  applica-
                  tions.

           milter_macro_v ($mail_name $mail_version)
                  The {v} macro value for Milter (mail filter) applications.

           milter_connect_timeout (30s)
                  The time limit for connecting to a Milter (mail filter) applica-
                  tion, and for negotiating protocol options.

           milter_command_timeout (30s)
                  The time limit for sending an SMTP command  to  a  Milter  (mail
                  filter) application, and for receiving the response.

           milter_content_timeout (300s)
                  The  time  limit  for  sending message content to a Milter (mail
                  filter) application, and for receiving the response.

           milter_connect_macros (see 'postconf -d' output)
                  The macros that are sent to Milter  (mail  filter)  applications
                  after completion of an SMTP connection.

           milter_helo_macros (see 'postconf -d' output)
                  The  macros  that  are sent to Milter (mail filter) applications
                  after the SMTP HELO or EHLO command.

           milter_mail_macros (see 'postconf -d' output)
                  The macros that are sent to Milter  (mail  filter)  applications
                  after the SMTP MAIL FROM command.

           milter_rcpt_macros (see 'postconf -d' output)
                  The  macros  that  are sent to Milter (mail filter) applications
                  after the SMTP RCPT TO command.

           milter_data_macros (see 'postconf -d' output)
                  The macros that are sent to version 4  or  higher  Milter  (mail
                  filter) applications after the SMTP DATA command.

           milter_unknown_command_macros (see 'postconf -d' output)
                  The  macros  that  are  sent to version 3 or higher Milter (mail
                  filter) applications after an unknown SMTP command.

           milter_end_of_data_macros (see 'postconf -d' output)
                  The macros that are sent to Milter  (mail  filter)  applications
                  after the message end-of-data.

           Available in Postfix version 2.5 and later:

           milter_end_of_header_macros (see 'postconf -d' output)
                  The  macros  that  are sent to Milter (mail filter) applications
                  after the end of the message header.

           Available in Postfix version 2.7 and later:

           milter_header_checks (empty)
                  Optional lookup tables for content inspection of message headers
                  that are produced by Milter applications.

           Available in Postfix version 3.1 and later:

           milter_macro_defaults (empty)
                  Optional  list  of  name=value pairs that specify default values
                  for arbitrary macros that Postfix may send  to  Milter  applica-
                  tions.

    MIME PROCESSING CONTROLS
           Available in Postfix version 2.0 and later:

           disable_mime_input_processing (no)
                  Turn off MIME processing while receiving mail.

           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.

           strict_8bitmime (no)
                  Enable both strict_7bit_headers and strict_8bitmime_body.

           strict_7bit_headers (no)
                  Reject mail with 8-bit text in message headers.

           strict_8bitmime_body (no)
                  Reject 8-bit message body text without 8-bit MIME content encod-
                  ing information.

           strict_mime_encoding_domain (no)
                  Reject  mail with invalid Content-Transfer-Encoding: information
                  for the message/* or multipart/* MIME content types.

           Available in Postfix version 2.5 and later:

           detect_8bit_encoding_header (yes)
                  Automatically detect 8BITMIME body content by  looking  at  Con-
                  tent-Transfer-Encoding:   message  headers;  historically,  this
                  behavior was hard-coded to be "always on".

    AUTOMATIC BCC RECIPIENT CONTROLS
           Postfix can automatically add BCC (blind carbon copy) when mail  enters
           the mail system:

           always_bcc (empty)
                  Optional  address  that  receives  a "blind carbon copy" of each
                  message that is received by the Postfix mail system.

           Available in Postfix version 2.1 and later:

           sender_bcc_maps (empty)
                  Optional BCC (blind carbon-copy) address lookup tables,  indexed
                  by envelope sender address.

           recipient_bcc_maps (empty)
                  Optional  BCC (blind carbon-copy) address lookup tables, indexed
                  by envelope recipient address.

    ADDRESS TRANSFORMATION CONTROLS
           Address rewriting is delegated to the trivial-rewrite(8)  daemon.   The
           cleanup(8) server implements table driven address mapping.

           empty_address_recipient (MAILER-DAEMON)
                  The recipient of mail addressed to the null address.

           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.

           sender_canonical_maps (empty)
                  Optional  address  mapping lookup tables for envelope and header
                  sender addresses.

           masquerade_classes (envelope_sender, header_sender, header_recipient)
                  What addresses are subject to address masquerading.

           masquerade_domains (empty)
                  Optional list of  domains  whose  subdomain  structure  will  be
                  stripped off in email addresses.

           masquerade_exceptions (empty)
                  Optional  list  of  user names that are not subjected to address
                  masquerading,  even  when  their   addresses   match   $masquer-
                  ade_domains.

           propagate_unmatched_extensions (canonical, virtual)
                  What  address  lookup  tables copy an address extension from the
                  lookup key to the lookup result.

           Available before Postfix version 2.0:

           virtual_maps (empty)
                  Optional lookup tables with a) names of domains  for  which  all
                  addresses  are  aliased  to  addresses  in other local or remote
                  domains, and b) addresses that are aliased to addresses in other
                  local or remote domains.

           Available in Postfix version 2.0 and later:

           virtual_alias_maps ($virtual_maps)
                  Optional lookup tables that are often searched with a full email
                  address (including domain) and that  apply  to  all  recipients:
                  local(8),  virtual,  and  remote; this is unlike alias_maps that
                  are only searched with an email address  localpart  (no  domain)
                  and that apply only to local(8) recipients.

           Available in Postfix version 2.2 and later:

           canonical_classes  (envelope_sender, envelope_recipient, header_sender,
           header_recipient)
                  What addresses are subject to canonical_maps address mapping.

           recipient_canonical_classes (envelope_recipient, header_recipient)
                  What  addresses  are subject to recipient_canonical_maps address
                  mapping.

           sender_canonical_classes (envelope_sender, header_sender)
                  What addresses are subject to sender_canonical_maps address map-
                  ping.

           remote_header_rewrite_domain (empty)
                  Rewrite  or  add  message headers in mail from remote clients if
                  the remote_header_rewrite_domain parameter value  is  non-empty,
                  updating  incomplete  addresses with the domain specified in the
                  remote_header_rewrite_domain parameter, and adding missing head-
                  ers.

    RESOURCE AND RATE CONTROLS
           duplicate_filter_limit (1000)
                  The maximal number of addresses remembered by the address dupli-
                  cate filter for aliases(5) or virtual(5) alias expansion, or for
                  showq(8) queue displays.

           header_size_limit (102400)
                  The  maximal  amount  of  memory  in bytes for storing a message
                  header.

           hopcount_limit (50)
                  The maximal number of Received:  message headers that is allowed
                  in the primary message headers.

           in_flow_delay (1s)
                  Time  to  pause before accepting a new message, when the message
                  arrival rate exceeds the message delivery rate.

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

           Available in Postfix version 2.0 and later:

           header_address_token_limit (10240)
                  The  maximal  number of address tokens are allowed in an address
                  message header.

           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.

           queue_file_attribute_count_limit (100)
                  The maximal number of (name=value) attributes that may be stored
                  in a Postfix queue file.

           Available in Postfix version 2.1 and later:

           virtual_alias_expansion_limit (1000)
                  The maximal number of addresses  that  virtual  alias  expansion
                  produces from each original recipient.

           virtual_alias_recursion_limit (1000)
                  The maximal nesting depth of virtual alias expansion.

           Available in Postfix version 3.0 and later:

           virtual_alias_address_length_limit (1000)
                  The  maximal  length  of  an  email  address after virtual alias
                  expansion.

    SMTPUTF8 CONTROLS
           Preliminary SMTPUTF8 support is introduced with Postfix 3.0.

           smtputf8_enable (yes)
                  Enable preliminary SMTPUTF8 support for the protocols  described
                  in RFC 6531, RFC 6532, and RFC 6533.

           smtputf8_autodetect_classes (sendmail, verify)
                  Detect  that  a message requires SMTPUTF8 support for the speci-
                  fied mail origin classes.

           Available in Postfix version 3.2 and later:

           enable_idna2003_compatibility (no)
                  Enable  'transitional'  compatibility   between   IDNA2003   and
                  IDNA2008,  when  converting UTF-8 domain names to/from the ASCII
                  form that is used for DNS lookups.

    TLS SUPPORT
           Available in Postfix version 3.10 and later:

           tls_required_enable (yes)
                  Enable  support  for  the  "TLS-Required:  no"  message  header,
                  defined in RFC 8689.

           requiretls_esmtp_header (yes)
                  Record  the  ESMTP  REQUIRETLS  request in a "Require-TLS-ESMTP:
                  yes" message header.

    MISCELLANEOUS CONTROLS
           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 delay values.

           delay_warning_time (0h)
                  The  time  after which the sender receives a copy of the message
                  headers of mail that is still queued.

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

           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.

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

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

           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.

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

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

           syslog_facility (mail)
                  The syslog facility of Postfix logging.

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

           Available in Postfix version 2.1 and later:

           enable_original_recipient (yes)
                  Enable  support  for  the  original  recipient  address after an
                  address is rewritten to a different address  (for  example  with
                  aliasing or with canonical mapping).

           Available in Postfix 3.3 and later:

           service_name (read-only)
                  The master.cf service name of a Postfix daemon process.

           Available in Postfix 3.5 and later:

           info_log_address_format (external)
                  The  email  address  form that will be used in non-debug logging
                  (info, warning, etc.).

           Available in Postfix 3.9 and later:

           force_mime_input_conversion (no)
                  Convert body content that claims to be 8-bit into  quoted-print-
                  able,  before  header_checks,  body_checks,  Milters, and before
                  after-queue content filters.

    FILES
           /etc/postfix/canonical*, canonical mapping table
           /etc/postfix/virtual*, virtual mapping table

    SEE ALSO
           trivial-rewrite(8), address rewriting
           qmgr(8), queue manager
           header_checks(5), message header content inspection
           body_checks(5), body parts content inspection
           canonical(5), canonical address lookup table format
           virtual(5), virtual alias lookup table format
           postconf(5), configuration parameters
           master(5), generic daemon options
           master(8), process manager
           postlogd(8), Postfix logging
           syslogd(8), system logging

    README FILES
           ADDRESS_REWRITING_README Postfix address manipulation
           CONTENT_INSPECTION_README content inspection

    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

           Wietse Venema
           Google, Inc.
           111 8th Avenue
           New York, NY 10011, USA

           Wietse Venema
           porcupine.org

                                                                        CLEANUP(8)