Jim,
I don't see a problem, other than people trying to deliver email to your MX to invalid recipients and from clients w/no rDNS. Your MX is rejecting them.
My mail server handles a trivial amount of mail so I panicked upon seeing the dramatic increase in log traffic. Further compounding matters is my inexperience with what are likely commonplace occurrences on busier mail servers.
"Backscatter" is when you *bounce* something to an alleged sender. You're not back-scattering, from what I can see, but merely rejecting.
Thanks. Once the sick feeling in my stomach subsided and I started seeing things a bit more clearly, I realized that I just probably had to ride it out. Thanks for your help! Sincerely, Gary Chambers
