Spamdies I’ll check out the link.
Tedob1
The volume of messages I’ve not tracked. What I’m seeing are aprox. 250-400 NDR’s daily.

Palemoon I’ll look at the PIX again. I didn’t setup the Exchange box but all the settings seem like the default’s. I just enabled recursive lookups, I only have 80 users I figure the server should be able to handle the extra load as long as the mail is legitimate. I can see multiple connections not associated with my domain any are smtp some are not (ports 1025, 43258, 43285, 43572, 43875, 44213, and 44511. That’s an eye opener.

Mohaughn: What type of volume for NDR’s would seem unusual for 80 users?

Thanks everyone. You all have helped me a great deal.