Dependencies:
The policy server is based on the Twisted networking engine. In ubuntu, Twisted can be installed with this command:
Or you can download and install it from source: Twisted homepage
Installation procedure:
$ID is obtained when you subscribe to the service, or omited for use with the limited public service. There should now be a daemon process answering requests on the local network interface (127.0.0.1), port 9998.
Test it:
Now you can plug the policy server into your postfix server. Alter your /etc/postfix/main.cf:
You should see the quorum URLs in your log files for senders who are rejected and in email headers of messages that are accepted. This is useful if you want to track down problems related to a particular sender or recipient.
If you would like to try the service for a while without rejecting any mail, you can use the --tagonly flag when invoking the policy_server.py daemon. In this mode, the policy server will instruct postfix to tag message headers with 'DEFER', 'REJECT' or 'ALLOW'. These results will be placed in a new x-quorum header along with the appropriate quorum.to link.