I am using MS Exchange Server 2003. Everything works fine, al DNS settings etc. are doublechecked, all ok. The server does not have any performance problems: enough memory, processor resources, etc.
However I do have one problem. The problem is greylisting. Sometimes when we send e-mails to servers that use greylisting, our server doesn't cooperate, meaning that the request for resending the e-mail is ignored. This is not always the case, sometime our server does resend the messages.
Now the really strange thing:
Only when I restart the Exchange server, the users receive undeliverable reports of messages that they have send in the past. All these undeliverable reports are from messages that were sent to servers that use greylisting. So I guess these are the undeliverable greylisted messages that our server didn't resend.
Why doesn't my server resend the graylisted messages?
Why do the senders of these messages only get a undeliverable messages after I restart the server?