Incoming mail ok, some outbound mail fails

[unHookt]

Recently, users starting receiving Delay Notifications and NDRs while sending messages to valid addresses that have worked in the past. Some messages get through just fine, others just sit in the queue.

Inbound mail delivery is fine. Also, offsite POP3 users have been having trouble connecting to the mail server, receiving "server timeout" and "connection reset by the server" error messages.

Sometimes, the Microsoft Information Store or MTA Stacks services will fail on launch, but without an error code ("//%&quot in the Event Log.

I have tried updating to SP3, installing the SMTP buffer overflow patch released 10/15, and installing the SP3 rollup update. No progress.

Any thoughts?

 

[ZipAss]

I have kinda the same issue with the delay notifications being received by some outbound email. These email messages stay in the smtp queue and may get delivered within a few days. But I also get an error message in the queued message stating "Unable to bind to the destination server DNS" or "The connection was dropped by the remote host". But inbound email works just fine. I looked up these 2 errors on MS and all tested ok. I am at Win2K SP4, Exch2K SP3.

Any ideas....?
thanks

 

[unHookt]

BTW, I have already ensured that I have a reverse DNS entry properly established for the domain. Any other suggestions?

Thanks!