Not getting any mail

[addihetja]

I've set up OSTicket 1.6RC5 on debian (testing). I've ironed out all the errors (needed to install a bunch of php5 modules before cron.php ran quietly) but I still don't get any mails into the system and therefore no new tickets get created.

I've checked the mail server logs and the only IMAP/POP activity happens when I modify the mail queue; nothing shows up in the system log when I run cron.php. What could I be missing?