I think my Exchange (SBS) server may be being used as an open relay or has been hacked (password guess). I have several messages in the outbound queue(s) to places that are "obviously" not something work related and very SPAM looking to say the least. This has happened before on another Exchange Server and I "fixed it" by changing the administrator password, deleting the messages from the queues and rebooting the server.
This time it's on another server (colleague of mine). Their server was pretty "default", so I created a new admin account and disabled the default "administrator", put a strong password on the new account, checked all the MS articles about verifying that the server is "locked down" so as not to be an open relay - the are locked down - the server is NOT an open relay, but the messages are still flowing out. Not very many - probably less than 100 per day. The sender is "email@example.com".
Is there any way to tell if a client computer in the office is sending these or if a user account has authenticated to Exchange to send these messages and which one it is. That is the only other thing I can think of. The guest account it disabled too FYI. I read the article on relaying and saw about setting up monitoring to check but no events matching that in the app log (1708 I believe).
Any suggestions would be appreciated - I told the guy to have all his users change their passwords. I am out of ideas at this point.