So, I'm about at my wits end with this spam, and I'm not sure what else to do.
Just this morning, most of our staff and teachers were getting a lot of spam messages from all over the place. I'm thinking it has to be some kind of attack because we haven't had that many spam messages come in before today. I already have multiple anti-spam filters put in place (Spamhaus, Barracuda, Sorbs, etc.), I already checked to see if we had some kind of open relay on our server (we don't), and I did notice that we had a lot of odd domains in our queue viewer that I had already removed. Even then, teachers and staff are still getting these spam messages that are getting by our anti-spam filters.
Anyone have any ideas where else I should look to resolve this? I'm using Exchange 2010 SP2.
Thanks!