Few days ago our email system was flooded with several thousand emails in a matter of minutes. All were bounce backs of legitmates emails sent out several months ago.
I am running Symantec smtp gateway 4 for AV filtering and exchange 2003.
Question iwhere were the bounce backs all this time, why did i get them now and not when i was supposed to. I know the emails came from the gateway but i'm not sure how to tell if they were generated at the original time and never delivered, generated a few days ago when it happened (if so, why did it take 2 months for it to generate a ndr) or could there be other reasons altogether.
I went into the gateway logs for one of the bounce backs. When i sent it originally the log states that Action:message delivery attemp failed , Last response: could not connect to server. Then i received a ndr a few days ago after sending it out 2 months ago.
Also, not sure if its relevant but i am running BGP and i had a failure of my primary ISP an hour before all this happened. The session wasn't shutdown properly and we never kicked over to our secondary isp. Our primary came back up within 2 minutes.
Big question, are are my bounce backs so late.