I've got a citadel server set up with it's own internal ip address and I am having trouble getting it to receive email.

I have open the ports for SMTPS and IMAPS along with HTTPS, I want to use SSL wherever possible and I can access it externally with firefox and thunderbird and send email using SMTPS.

However, I cannot get it to receive email, sent email never arrived, which port is sent email received by and therefore which should I forward the MTA on my mail server.

I am currently using the citadel generated key, could that be the problem.