postfix-policyd-spf-perl/debian/postfix-policyd-spf-perl.8
2007-04-18 18:41:31 +00:00

266 lines
8.2 KiB
Groff

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.\"
.IX Title "postfix-policyd-spf-perl 1p"
.TH postfix-policyd-spf-perl 8p "2007-04-18"
.SH "NAME"
postfix-policyd-spf-perl \- pure-Perl Postfix policy daemon for SPF checking
.SH "VERSION"
.IX Header "VERSION"
2\.004
.SH "USAGE"
.IX Header "USAGE"
Usage:
policyd-spf-perl [-v]
.SH "OTHER DOCUMENTATION"
.IX Header "OTHER DOCUMENTATION"
This documentation assumes you have read Postfix's README_FILES/
SMTPD_POLICY_README.
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
postfix-policyd-spf-perl is a Postfix SMTPd policy daemon for SPF checking.
It is implemented in pure Perl and uses the Mail::SPF CPAN module. Note that
Mail::SPF is a complete re-implementation of SPF based on the final SPF RFC,
RFC 4408. It shares no code with the older Mail::SPF::Query that was the
original SPF development implementation. If you are upgrading from on older
version of this policy server you will need to install Mail::SPF.
This version of the policy server always checks HELO before Mail From (older
versions just checked HELO if Mail From was null). It will reject mail that
fails either Mail From or HELO SPF checks. It will defer mail if there is a
temporary SPF error and the message would othersise be permitted
(DEFER_IF_PERMIT). If the HELO check produces a REJECT/DEFER result, Mail From
will not be checked.
If the message is not rejected or deferred, the policy server will PREPEND the
appropriate SPF Received header. If Mail From is anything other than completely
empty (i.e. <>) then the Mail From result will be used for SPF Received (e.g.
Mail From None even if HELO is Pass).
The policy server skips SPF checks for connections from the localhost (127.) and
instead prepends and logs 'SPF skipped - localhost is always allowed.' If you
have relays that you want to skip SPF checks for, you can add them to
relay_addresses on line 78 using standard CIDR notation in a space separated
list. For these addresses, 'X-Comment: SPF skipped for whitelisted relay' is
prepended and logged.
Error conditions within the policy server (that don't result in a crash) or from
Mail::SPF will return DUNNO.
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
Logging is sent to syslogd.
Each time a Postfix SMTP server process is started it connects to the policy
service socket and Postfix runs one instance of this Perls script. By
default, a Postfix SMTP server process terminates after 100 seconds of idle
time, or after serving 100 clients. Thus, the cost of starting this Perl
script is smoothed over time
The default policy_time_limit is 1000 seconds. This may be too short for some
SMTP transactions to complete. As recommended in SMTPD_POLICY_README, this
should be extended to 3600 seconds. To do so, set "policy_time_limit = 3600"
in /etc/postfix/main.cf.
.SH "TESTING THE POLICY DAEMON"
.IX Header "TESTING THE POLICY DAEMON"
Testing the policy daemon
To test the policy daemon by hand, execute:
% perl /usr/sbin/postfix-policyd-spf-perl
Each query is a bunch of attributes. Order does not matter, and the daemon
uses only a few of all the attributes shown below:
request=smtpd_access_policy
protocol_state=RCPT
protocol_name=SMTP
helo_name=some.domain.tld
queue_id=
instance=71b0.45e2f5f1.d4da1.0
sender=foo@bar.tld
recipient=bar@foo.tld
client_address=1.2.3.4
client_name=another.domain.tld
[empty line]
The policy daemon will answer in the same style, with an attribute list
followed by a empty line:
action=550 Please see http://www.openspf.org/Why?id=foo@bar.tld&ip=1.2.3.4&
receiver=bar@foo.tld
[empty line]
To test HELO checking sender should be empty:
sender=
... More attributes...
[empty line]
If you want more detail in the system logs change $VERBOSE to 1.
.SH "POSTFIX INTEGRATION"
.IX Header "POSTFIX INTEGRATION"
1. Add the following to /etc/postfix/master.cf:
policy unix - n n - - spawn
user=nobody argv=/usr/bin/perl /usr/sbin/policyd-spf-perl
2. Configure the Postfix policy service in /etc/postfix/main.cf:
smtpd_recipient_restrictions =
...
reject_unauth_destination
check_policy_service unix:private/policy
...
policy_time_limit = 3600
NOTE: Specify check_policy_service AFTER reject_unauth_destination or
else your system can become an open relay.
3. Restart Postfix.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
libmail-spf-perl, <http://www.openspf.org>
.SH "AUTHORS"
.IX Header "AUTHORS"
This version of \fBpolicyd-spf-perl\fR was written by Meng Weng Wong
<mengwong+spf@pobox.com> and updated for libmail-spf-perl by Scott Kitterman
<scott@kitterman.com> and Julian Mehnle <julian@mehnle.net>.
.PP
This man-page was written by Scott Kitterman <scott@kitterman.com>.