.TH DNSBLOG 8postfix 
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.SH NAME
dnsblog
\-
Postfix DNS allow/denylist logger
.SH "SYNOPSIS"
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\fBdnsblog\fR [generic Postfix daemon options]
.SH DESCRIPTION
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The \fBdnsblog\fR(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
\fBpostscreen\fR(8) server.
.SH "PROTOCOL"
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With each connection, the \fBdnsblog\fR(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
\fBdnsblog\fR(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 \fBdnsblog\fR(8) server closes the connection.
.SH DIAGNOSTICS
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Problems and transactions are logged to \fBsyslogd\fR(8)
or \fBpostlogd\fR(8).
.SH "CONFIGURATION PARAMETERS"
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Changes to \fBmain.cf\fR are picked up automatically, as
\fBdnsblog\fR(8) processes run for only a limited amount
of time. Use the command "\fBpostfix reload\fR" to speed
up a change.

The text below provides only a parameter summary. See
\fBpostconf\fR(5) for more details including examples.
.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 "\fBpostscreen_dnsbl_sites (empty)\fR"
Optional list of patterns with DNS allow/denylist domains, filters
and weight
factors.
.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"
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smtpd(8), Postfix SMTP server
postconf(5), configuration parameters
postlogd(8), Postfix logging
syslogd(8), system logging
.SH "LICENSE"
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The Secure Mailer license must be distributed with this software.
.SH HISTORY
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This service was introduced with Postfix version 2.8.
.SH "AUTHOR(S)"
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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