Route Local mail in EXIM

Question

Can I route all local Email (local domain to local domain) to another host ex: a spam filtering system on EXIM?

Answer 1

You can't easily do this, and normally wouldn't need to do that. If you find a local user is spamming you it is usually easy to deal with. Spam filtering is usually done for mail coming from servers you don't have control of.

You could try with a base configuration using the remote server as a smart host for all deliveries. It would need to know to route the message back after scanning. You would then need to configure your smarthost routing to skip messages arriving from the system doing spam filtering.

Answer 2

It's difficult to extrapolate exactly what you're trying to achieve by your description. If your goal is to distribute the load of spam scanning to a seperate machine, then you can configure Exim to speak to SpamAssassin on a different machine. Spamassassin listens on a TCP port, normally 127.0.0.1 port 783. You can, on the other server, configure Spamassassin to listen to the IP of eth0 (or whatever is your internal network interface), and then just configure Exim as per Section 2 and Section 3 of this chapter of the Exim docs:

http://www.exim.org/exim-html-current/doc/html/spec_html/ch43.html