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
       eventually 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 resulting 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
       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.

       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.

       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
              example, "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)