Spam and virus filter stopped working
I have a server set up mostly following the perfect setup for Debian 4. It's been working fine for about 2 months now. Today I suddenly got a heap of spam in my inbox. There were no more headers in the messages indicating that they had been scanned by my server. These headers used to be there but simply vanished. I can't find anything in any logfile that makes sense to me (mail.log, mail.err, mail.info, syslog, messages). It also appears as though freshclam stopped updating after yesterday.. for no apparent reason. I upgraded to the latest version of ispconfig just now, but that doesn't help.
I only have a fuzzy understanding of how the whole process goes from mail arriving at my server to it being delivered to the mailboxes. Can anyone tell me where to look for clues?