postfix-policyd-spf-perl 2.000
A Postfix SMTPd policy server for SPF checking
(C) 2007      Scott Kitterman <scott@kitterman.com>
    2003-2004 Meng Weng Wong <mengwong@pobox.com>
Thanks for contributions by various members of the SPF project
<http://www.openspf.org/Software#postfix-policyd-spf-perl>
==============================================================================

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.  In the case of multi-recipient mail, multiple 
headers will get appended.  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.'

Error conditions within the policy server (that don't result in a crash) or from 
Mail::SPF will return DUNNO.  

See INSTALL for installation instructions.

Usage:
    policyd-spf-perl [-v]

This documentation assumes you have read Postfix's README_FILES/
SMTPD_POLICY_README.

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 Perl 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 out 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.

Testing the policy daemon
-------------------------

To test the policy daemon by hand, execute:

    % perl /usr/lib/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=8045F2AB23
    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.

License
-------

postfix-policyd-spf-perl is free software.  You may use, modify, and distribute
it under the GNU GPL (version 2 or later); see the LICENSE file.