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)