I am having a nightmare with our exchange server getting blocklisted every now and again. The queues appear to be filling up with junk emails. I have ran scans on the server a number of times but nothing has been found. ie. sophos, adaware, and all known good scans have been done.
The server is an exchange 2003 box with around 100+ users on it so it is business critical.
How should I go about finding the culprit machine or mailbox spitting spam. Should I network monitor it (which slows the computer down massively) or any other way?
in order to send emails out temporarily, we are using a borrowed smart host but need to eradicate the issue sooner rather than later.
looking forward to some expert advice.