Message cannot be sent to domains with MX record pointing to IP or CNAME record in Exchange 2000 Server

If you configure the Simple Mail Transfer Protocol (SMTP) virtual server to use an external Domain Name System (DNS) server in the Advanced Delivery dialog box, messages to some domains may remain in the SMTP queue, and the queue status may be "The remote server did not respond to a connection attempt."

There are two possible causes of this problem. To determine which of the following is the cause, use the Nslookup utility to query the remote domains.

Possible cause 1

You may find that there is a mail exchange (MX) record that points to a CNAME record in the DNS server. The CNAME record points to a valid host record. This problem occurs because Microsoft Exchange 2000 Server does not correctly process the DNS query result in such a scenario.

Possible cause 2

You may find that the MX record points to an IP address. Although the IP address belongs to a valid host, Exchange 2000 does not correctly process the DNS query result in such a scenario.

To resolve this problem, obtain the latest service pack for Microsoft Exchange 2000 Server. For additional information, click the following article number to view the article in the Microsoft Knowledge Base: The English version of this fix should have the following file attributes or later:

Component: SMTP

Microsoft has confirmed that this is a problem in Microsoft Exchange 2000 Server. This problem was first corrected in Microsoft Exchange 2000 Server Service Pack 1.