Looked for this, and thought it would be in smtpd.cfg but can't see from examples.
Basically, we have a fax server that will integrate with an SMTP server to allow emails to be sent/received over email. The way it does this is to use a dummy domain to which you address your 'emails' to that then get forwarded into the fax server, ie 448450037319@fax would get passed through.
So, what I need to do is allow Scalix to accept mail addressed to @fax (easy, done) and then relay / forward / somehow to another box on my lan. Can't see how though.
Only Stop gap, which I haven't tried, and appreciate heads up on whether it will work, is to take @fax domain out of sca, but put a relay line in smtpd.cfg so mail to @fax is allowed, and then create a dummy MX record on the internal DNS server to point it back at the fax box. Am sure there's a million flaws in that idea so a better method welcomed please!