Is it possible to run a postfix server on a pfSense box? I currently run a FreeBSD 4.11 firewall and run qmail on it. I want/need to build a new firewall and I like what pfSense has to offer, but I have only one box for a firewall/mail server.
It's not supported but possible. However things might break on upgrading your box. Also be prepared that some files are generated dynamically on bootup ot configuration changes.
Ive started on an Exim package, and although its far from complete its definitely very possible to add this. The only problem is, has Hoba has said, is how to handle the upgrading etc. which I havent even looked at just yet.
Currently the package supports:
Quotas per mailbox
Subnets that are allowed to relay
SMTP Auth (both client side and server side)
and numerous other smaller settings. Its not at a point where I am comfortable with it as there is still too many settings that are hard coded and these settings should be configured via the web interface.
It gets tricky when adding users though cos you will need to support aliases, forwarding and possibly store and forwarding. You also then need to decide whether you have to store the mail locally (requires some POP3 or IMAP server) or whether it should just act as a mailhub for an internal mail server(s).