XIMS: Internet Mail Service Incorrectly Returns Non-Delivery Report Message or Silently Drops E-Mail Message

When you send an e-mail message, if the Domain Name System (DNS) records for a target domain are unreachable or a remote server denies the Internet Protocol (IP) address of the Exchange Server computer, the Internet Mail Service may either silently drop the e-mail message or incorrectly return a non-delivery report (NDR) message without trying to send the message again. This occurs even though the Internet Mail Service should try to send the e-mail message again, because at least one IP address may be temporarily unreachable.

This issue can occur if the Exchange Server computer incorrectly sets retry for an outbound message when there are several mail exchanger (MX) records for a target domain in DNS.

To resolve this problem, obtain the latest service pack for Exchange Server 5.5. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

Microsoft has confirmed that this is a problem in Microsoft Exchange Server version 5.5. This problem was first corrected in Exchange Server 5.5 Service Pack 4.