Страницы справочника OS X

Эта страница руководства для  версии 10.9 Mac OS X

Читать страницы руководства

VERIFY(8)                                                                                          VERIFY(8)



NAME
       verify - Postfix address verification server

SYNOPSIS
       verify [generic Postfix daemon options]

DESCRIPTION
       The verify(8) address verification server maintains a record of what recipient addresses are known to
       be deliverable or undeliverable.

       Addresses are verified by injecting probe messages into the Postfix queue.  Probe  messages  are  run
       through  all  the routing and rewriting machinery except for final delivery, and are discarded rather
       than being deferred or bounced.

       Address verification relies on the answer from the nearest MTA for the specified  address,  and  will
       therefore not detect all undeliverable addresses.

       The  verify(8)  server is designed to run under control by the Postfix master server. It maintains an
       optional persistent database.  To avoid being interrupted by "postfix stop" in the middle of a  data-base database
       base update, the process runs in a separate process group.

       The verify(8) server implements the following requests:

       update address status text
              Update the status and text of the specified address.

       query address
              Look  up  the status and text for the specified address.  If the status is unknown, a probe is
              sent and an "in progress" status is returned.

SECURITY
       The address verification server is not security-sensitive. It does not talk to the  network,  and  it
       does not talk to local users.  The verify server can run chrooted at fixed low privilege.

       The  address  verification  server can be coerced to store unlimited amounts of garbage. Limiting the
       cache expiry time trades one problem (disk space exhaustion) for another one (poor response  time  to
       client requests).

       With  Postfix version 2.5 and later, the verify(8) server no longer uses root privileges when opening
       the address_verify_map cache file. The file should now be stored under the Postfix-owned  data_direc-tory. data_directory.
       tory.   As  a  migration  aid, an attempt to open a cache file under a non-Postfix directory is redi-rected redirected
       rected to the Postfix-owned data_directory, and a warning is logged.

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

BUGS
       Address verification probe messages add additional traffic to the mail queue.  Recipient verification
       may  cause  an increased load on down-stream servers in the case of a dictionary attack or a flood of
       backscatter bounces.  Sender address verification may cause your  site  to  be  blacklisted  by  some
       providers.

       If  the persistent database ever gets corrupted then the world comes to an end and human intervention
       is needed. This violates a basic Postfix principle.

CONFIGURATION PARAMETERS
       Changes to main.cf are not picked up automatically, as verify(8) processes are  long-lived.  Use  the
       command "postfix reload" after a configuration change.

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

PROBE MESSAGE CONTROLS
       address_verify_sender ($double_bounce_sender)
              The sender address to use in address verification probes; prior to Postfix 2.5 the default was
              "postmaster".

       Available with Postfix 2.9 and later:

       address_verify_sender_ttl (0s)
              The  time  between  changes in the time-dependent portion of address verification probe sender
              addresses.

CACHE CONTROLS
       address_verify_map (see 'postconf -d' output)
              Lookup table for persistent address verification status storage.

       address_verify_positive_expire_time (31d)
              The time after which a successful probe expires from the address verification cache.

       address_verify_positive_refresh_time (7d)
              The time after which a successful address verification probe needs to be refreshed.

       address_verify_negative_cache (yes)
              Enable caching of failed address verification probe results.

       address_verify_negative_expire_time (3d)
              The time after which a failed probe expires from the address verification cache.

       address_verify_negative_refresh_time (3h)
              The time after which a failed address verification probe needs to be refreshed.

       Available with Postfix 2.7 and later:

       address_verify_cache_cleanup_interval (12h)
              The amount of time between verify(8) address verification database cleanup runs.

PROBE MESSAGE ROUTING CONTROLS
       By default, probe messages are delivered via the same  route  as  regular  messages.   The  following
       parameters can be used to override specific message routing mechanisms.

       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.

       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.

       Available in Postfix 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 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  verifica-tion verification
              tion 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.

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

       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.

       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, "postfix/smtpd".

SEE ALSO
       smtpd(8), Postfix SMTP server
       cleanup(8), enqueue Postfix message
       postconf(5), configuration parameters
       syslogd(5), system logging

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

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

HISTORY
       This service was introduced with Postfix version 2.1.

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



                                                                                                   VERIFY(8)