Updated: 2022/Sep/29

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TRIVIAL-REWRITE(8)          System Manager's Manual         TRIVIAL-REWRITE(8)




NAME
       trivial-rewrite - Postfix address rewriting and resolving daemon

SYNOPSIS
       trivial-rewrite [generic Postfix daemon options]

DESCRIPTION
       The trivial-rewrite(8) daemon processes three types of client service
       requests:

       rewrite context address
              Rewrite an address to standard form, according to the address
              rewriting context:

              local  Append the domain names specified with $myorigin or
                     $mydomain to incomplete addresses; do swap_bangpath and
                     allow_percent_hack processing as described below, and
                     strip source routed addresses (@site,@site:user@domain)
                     to user@domain form.

              remote Append the domain name specified with
                     $remote_header_rewrite_domain to incomplete addresses.
                     Otherwise the result is identical to that of the local
                     address rewriting context. This prevents Postfix from
                     appending the local domain to spam from poorly written
                     remote clients.

       resolve sender address
              Resolve the address to a (transport, nexthop, recipient, flags)
              quadruple. The meaning of the results is as follows:

              transport
                     The delivery agent to use. This is the first field of an
                     entry in the master.cf file.

              nexthop
                     The host to send to and optional delivery method
                     information.

              recipient
                     The envelope recipient address that is passed on to
                     nexthop.

              flags  The address class, whether the address requires relaying,
                     whether the address has problems, and whether the request
                     failed.

       verify sender address
              Resolve the address for address verification purposes.

SERVER PROCESS MANAGEMENT
       The trivial-rewrite(8) servers run under control by the Postfix
       master(8) server.  Each server can handle multiple simultaneous
       connections.  When all servers are busy while a client connects, the
       master creates a new server process, provided that the trivial-rewrite
       server process limit is not exceeded.  Each trivial-rewrite server
       terminates after serving at least $max_use clients of after $max_idle
       seconds of idle time.

STANDARDS
       None. The command does not interact with the outside world.

SECURITY
       The trivial-rewrite(8) daemon is not security sensitive.  By default,
       this daemon does not talk to remote or local users.  It can run at a
       fixed low privilege in a chrooted environment.

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

CONFIGURATION PARAMETERS
       On busy mail systems a long time may pass before a main.cf change
       affecting trivial-rewrite(8) is picked up. 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

       resolve_dequoted_address (yes)
              Resolve a recipient address safely instead of correctly, by
              looking inside quotes.

       Available with 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.

       Available with Postfix version 2.3 and later:

       resolve_numeric_domain (no)
              Resolve "user@ipaddress" as "user@[ipaddress]", instead of
              rejecting the address as invalid.

       Available with Postfix version 2.5 and later:

       allow_min_user (no)
              Allow a sender or recipient address to have `-' as the first
              character.

ADDRESS REWRITING CONTROLS

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

       allow_percent_hack (yes)
              Enable the rewriting of the form "user%domain" to "user@domain".

       append_at_myorigin (yes)
              With locally submitted mail, append the string "@$myorigin" to
              mail addresses without domain information.

       append_dot_mydomain (Postfix >= 3.0: no, Postfix < 3.0: yes)
              With locally submitted mail, append the string ".$mydomain" to
              addresses that have no ".domain" information.

       recipient_delimiter (empty)
              The set of characters that can separate an email address
              localpart, user name, or a .forward file name from its
              extension.

       swap_bangpath (yes)
              Enable the rewriting of "site!user" into "user@site".

       Available in Postfix 2.2 and later:

       remote_header_rewrite_domain (empty)
              Don't rewrite message headers from remote clients at all when
              this parameter is empty; otherwise, rewrite message headers and
              append the specified domain name to incomplete addresses.

ROUTING CONTROLS
       The following is applicable to Postfix version 2.0 and later.  Earlier
       versions do not have support for: virtual_transport, relay_transport,
       virtual_alias_domains, virtual_mailbox_domains or proxy_interfaces.

       local_transport (local:$myhostname)
              The default mail delivery transport and next-hop destination for
              final delivery to domains listed with mydestination, and for
              [ipaddress] destinations that match $inet_interfaces or
              $proxy_interfaces.

       virtual_transport (virtual)
              The default mail delivery transport and next-hop destination for
              final delivery to domains listed with $virtual_mailbox_domains.

       relay_transport (relay)
              The default mail delivery transport and next-hop destination for
              remote delivery to domains listed with $relay_domains.

       default_transport (smtp)
              The default mail delivery transport and next-hop destination for
              destinations that do not match $mydestination, $inet_interfaces,
              $proxy_interfaces, $virtual_alias_domains,
              $virtual_mailbox_domains, or $relay_domains.

       parent_domain_matches_subdomains (see 'postconf -d' output)
              A list of Postfix features where the pattern "example.com" also
              matches subdomains of example.com, instead of requiring an
              explicit ".example.com" pattern.

       relayhost (empty)
              The next-hop destination(s) for non-local mail; overrides
              non-local domains in recipient addresses.

       transport_maps (empty)
              Optional lookup tables with mappings from recipient address to
              (message delivery transport, next-hop destination).

       Available in Postfix version 2.3 and later:

       sender_dependent_relayhost_maps (empty)
              A sender-dependent override for the global relayhost parameter
              setting.

       Available in Postfix version 2.5 and later:

       empty_address_relayhost_maps_lookup_key (<>)
              The sender_dependent_relayhost_maps search string that will be
              used instead of the null sender address.

       Available in Postfix version 2.7 and later:

       empty_address_default_transport_maps_lookup_key (<>)
              The sender_dependent_default_transport_maps search string that
              will be used instead of the null sender address.

       sender_dependent_default_transport_maps (empty)
              A sender-dependent override for the global default_transport
              parameter setting.

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 delivered.  By default, address
       verification probes use the same route as regular mail. To override
       specific aspects of message routing for address verification probes,
       specify one or more of the following:

       address_verify_local_transport ($local_transport)
              Overrides the local_transport parameter setting for address
              verification probes.

       address_verify_virtual_transport ($virtual_transport)
              Overrides the virtual_transport parameter setting for address
              verification probes.

       address_verify_relay_transport ($relay_transport)
              Overrides the relay_transport parameter setting for address
              verification probes.

       address_verify_default_transport ($default_transport)
              Overrides the default_transport parameter setting for address
              verification probes.

       address_verify_relayhost ($relayhost)
              Overrides the relayhost parameter setting for address
              verification probes.

       address_verify_transport_maps ($transport_maps)
              Overrides the transport_maps parameter setting for address
              verification probes.

       Available in Postfix version 2.3 and later:

       address_verify_sender_dependent_relayhost_maps
       ($sender_dependent_relayhost_maps)
              Overrides the sender_dependent_relayhost_maps parameter setting
              for address verification probes.

       Available in Postfix version 2.7 and later:

       address_verify_sender_dependent_default_transport_maps
       ($sender_dependent_default_transport_maps)
              Overrides the sender_dependent_default_transport_maps parameter
              setting for address verification probes.

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.

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

       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.

       relocated_maps (empty)
              Optional lookup tables with new contact information for users or
              domains that no longer exist.

       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.

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

       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 2.0 and later:

       helpful_warnings (yes)
              Log warnings about problematic configuration settings, and
              provide helpful suggestions.

       Available in Postfix 3.3 and later:

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

SEE ALSO
       postconf(5), configuration parameters
       transport(5), transport table format
       relocated(5), format of the "user has moved" table
       master(8), process manager
       postlogd(8), Postfix logging
       syslogd(8), system logging

README FILES
       Use "postconf readme_directory" or "postconf html_directory" to locate
       this information.
       ADDRESS_CLASS_README, Postfix address classes howto
       ADDRESS_VERIFICATION_README, Postfix address verification

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



                                                            TRIVIAL-REWRITE(8)