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Diffstat (limited to 'man/man8/verify.8')
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diff --git a/man/man8/verify.8 b/man/man8/verify.8 new file mode 100644 index 0000000..7aece00 --- /dev/null +++ b/man/man8/verify.8 @@ -0,0 +1,257 @@ +.TH VERIFY 8 +.ad +.fi +.SH NAME +verify +\- +Postfix address verification server +.SH "SYNOPSIS" +.na +.nf +\fBverify\fR [generic Postfix daemon options] +.SH DESCRIPTION +.ad +.fi +The \fBverify\fR(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 \fBverify\fR(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 database update, the process runs in a separate process +group. + +The \fBverify\fR(8) server implements the following requests: +.IP "\fBupdate\fI address status text\fR" +Update the status and text of the specified address. +.IP "\fBquery\fI address\fR" +Look up the \fIstatus\fR and \fItext\fR for the specified +\fIaddress\fR. +If the status is unknown, a probe is sent and an "in progress" +status is returned. +.SH "SECURITY" +.na +.nf +.ad +.fi +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 \fBverify\fR(8) +server no longer uses root privileges when opening the +\fBaddress_verify_map\fR cache file. The file should now +be stored under the Postfix\-owned \fBdata_directory\fR. As +a migration aid, an attempt to open a cache file under a +non\-Postfix directory is redirected to the Postfix\-owned +\fBdata_directory\fR, and a warning is logged. +.SH DIAGNOSTICS +.ad +.fi +Problems and transactions are logged to \fBsyslogd\fR(8) +or \fBpostlogd\fR(8). +.SH BUGS +.ad +.fi +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 +denylisted 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. +.SH "CONFIGURATION PARAMETERS" +.na +.nf +.ad +.fi +Changes to \fBmain.cf\fR are not picked up automatically, +as \fBverify\fR(8) +processes are long\-lived. Use the command "\fBpostfix reload\fR" after +a configuration change. + +The text below provides only a parameter summary. See +\fBpostconf\fR(5) for more details including examples. +.SH "PROBE MESSAGE CONTROLS" +.na +.nf +.ad +.fi +.IP "\fBaddress_verify_sender ($double_bounce_sender)\fR" +The sender address to use in address verification probes; prior +to Postfix 2.5 the default was "postmaster". +.PP +Available with Postfix 2.9 and later: +.IP "\fBaddress_verify_sender_ttl (0s)\fR" +The time between changes in the time\-dependent portion of address +verification probe sender addresses. +.SH "CACHE CONTROLS" +.na +.nf +.ad +.fi +.IP "\fBaddress_verify_map (see 'postconf -d' output)\fR" +Lookup table for persistent address verification status +storage. +.IP "\fBaddress_verify_positive_expire_time (31d)\fR" +The time after which a successful probe expires from the address +verification cache. +.IP "\fBaddress_verify_positive_refresh_time (7d)\fR" +The time after which a successful address verification probe needs +to be refreshed. +.IP "\fBaddress_verify_negative_cache (yes)\fR" +Enable caching of failed address verification probe results. +.IP "\fBaddress_verify_negative_expire_time (3d)\fR" +The time after which a failed probe expires from the address +verification cache. +.IP "\fBaddress_verify_negative_refresh_time (3h)\fR" +The time after which a failed address verification probe needs to +be refreshed. +.PP +Available with Postfix 2.7 and later: +.IP "\fBaddress_verify_cache_cleanup_interval (12h)\fR" +The amount of time between \fBverify\fR(8) address verification +database cleanup runs. +.SH "PROBE MESSAGE ROUTING CONTROLS" +.na +.nf +.ad +.fi +By default, probe messages are delivered via the same route +as regular messages. The following parameters can be used to +override specific message routing mechanisms. +.IP "\fBaddress_verify_relayhost ($relayhost)\fR" +Overrides the relayhost parameter setting for address verification +probes. +.IP "\fBaddress_verify_transport_maps ($transport_maps)\fR" +Overrides the transport_maps parameter setting for address verification +probes. +.IP "\fBaddress_verify_local_transport ($local_transport)\fR" +Overrides the local_transport parameter setting for address +verification probes. +.IP "\fBaddress_verify_virtual_transport ($virtual_transport)\fR" +Overrides the virtual_transport parameter setting for address +verification probes. +.IP "\fBaddress_verify_relay_transport ($relay_transport)\fR" +Overrides the relay_transport parameter setting for address +verification probes. +.IP "\fBaddress_verify_default_transport ($default_transport)\fR" +Overrides the default_transport parameter setting for address +verification probes. +.PP +Available in Postfix 2.3 and later: +.IP "\fBaddress_verify_sender_dependent_relayhost_maps ($sender_dependent_relayhost_maps)\fR" +Overrides the sender_dependent_relayhost_maps parameter setting for address +verification probes. +.PP +Available in Postfix 2.7 and later: +.IP "\fBaddress_verify_sender_dependent_default_transport_maps ($sender_dependent_default_transport_maps)\fR" +Overrides the sender_dependent_default_transport_maps parameter +setting for address verification probes. +.SH "SMTPUTF8 CONTROLS" +.na +.nf +.ad +.fi +Preliminary SMTPUTF8 support is introduced with Postfix 3.0. +.IP "\fBsmtputf8_autodetect_classes (sendmail, verify)\fR" +Detect that a message requires SMTPUTF8 support for the specified +mail origin classes. +.PP +Available in Postfix version 3.2 and later: +.IP "\fBenable_idna2003_compatibility (no)\fR" +Enable 'transitional' compatibility between IDNA2003 and IDNA2008, +when converting UTF\-8 domain names to/from the ASCII form that is +used for DNS lookups. +.SH "MISCELLANEOUS CONTROLS" +.na +.nf +.ad +.fi +.IP "\fBconfig_directory (see 'postconf -d' output)\fR" +The default location of the Postfix main.cf and master.cf +configuration files. +.IP "\fBdaemon_timeout (18000s)\fR" +How much time a Postfix daemon process may take to handle a +request before it is terminated by a built\-in watchdog timer. +.IP "\fBipc_timeout (3600s)\fR" +The time limit for sending or receiving information over an internal +communication channel. +.IP "\fBprocess_id (read\-only)\fR" +The process ID of a Postfix command or daemon process. +.IP "\fBprocess_name (read\-only)\fR" +The process name of a Postfix command or daemon process. +.IP "\fBqueue_directory (see 'postconf -d' output)\fR" +The location of the Postfix top\-level queue directory. +.IP "\fBsyslog_facility (mail)\fR" +The syslog facility of Postfix logging. +.IP "\fBsyslog_name (see 'postconf -d' output)\fR" +A prefix that is prepended to the process name in syslog +records, so that, for example, "smtpd" becomes "prefix/smtpd". +.PP +Available in Postfix 3.3 and later: +.IP "\fBservice_name (read\-only)\fR" +The master.cf service name of a Postfix daemon process. +.SH "SEE ALSO" +.na +.nf +smtpd(8), Postfix SMTP server +cleanup(8), enqueue Postfix message +postconf(5), configuration parameters +postlogd(8), Postfix logging +syslogd(8), system logging +.SH "README FILES" +.na +.nf +.ad +.fi +Use "\fBpostconf readme_directory\fR" or +"\fBpostconf html_directory\fR" to locate this information. +.na +.nf +ADDRESS_VERIFICATION_README, address verification howto +.SH "LICENSE" +.na +.nf +.ad +.fi +The Secure Mailer license must be distributed with this software. +.SH HISTORY +.ad +.fi +.ad +.fi +This service was introduced with Postfix version 2.1. +.SH "AUTHOR(S)" +.na +.nf +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 |