man > dnsblog(8postfix)

DNSBLOG(8postfix)                                                                  DNSBLOG(8postfix)

NAME
       dnsblog - Postfix DNS allow/denylist logger

SYNOPSIS
       dnsblog [generic Postfix daemon options]

DESCRIPTION
       The  dnsblog(8) server implements an ad-hoc DNS allow/denylist lookup service. This may even‐
       tually be replaced by an UDP client that is built directly into the postscreen(8) server.

PROTOCOL
       With each connection, the dnsblog(8) server receives a DNS allow/denylist domain name, an  IP
       address, and an ID.  If the IP address is listed under the DNS allow/denylist, the dnsblog(8)
       server  logs the match and replies with the query arguments plus an address list with the re‐
       sulting IP addresses, separated by whitespace, and the reply TTL.  Otherwise it replies  with
       the  query  arguments  plus  an  empty address list and the reply TTL; the reply TTL is -1 if
       there is no reply, or a negative reply that contains no SOA record.  Finally, the  dnsblog(8)
       server closes the connection.

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

CONFIGURATION PARAMETERS
       Changes  to  main.cf are picked up automatically, as dnsblog(8) processes run for only a lim‐
       ited 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.

       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 ter‐
              minated by a built-in watchdog timer.

       postscreen_dnsbl_sites (empty)
              Optional list of DNS allow/denylist domains, filters and weight factors.

       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)
              A  prefix  that is prepended to the process name in syslog records, so that, for exam‐
              ple, "smtpd" becomes "prefix/smtpd".

       Available in Postfix 3.3 and later:

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

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

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

HISTORY
       This service was introduced with Postfix version 2.8.

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

                                                                                   DNSBLOG(8postfix)