System Requirements
-------------------

The following Perl version and packages are required for running
postfix-policyd-spf-perl:

  Perl 5.6
  version
  NetAddr-IP 4
  Mail-SPF (not Mail-SPF-Query)

Installing
----------

 1. Copy postfix-policyd-spf-perl to /usr/lib/postfix/policyd-spf-perl

 2. Add the following to /etc/postfix/master.cf:

        policy  unix  -       n       n       -       -       spawn
            user=nobody argv=/usr/bin/perl /usr/lib/postfix/policyd-spf-perl

 3. Configure the Postfix policy service in /etc/postfix/main.cf:

        smtpd_recipient_restrictions =
            ...
            reject_unauth_destination
            check_policy_service unix:private/policy
            ...

    NOTE:  Specify check_policy_service AFTER reject_unauth_destination or
    else your system can become an open relay.

 4. Restart Postfix.