XFOR: SMTP Messages Not Being Delivered to Certain Domains

ID: Q198981

The information in this article applies to:

Microsoft Exchange Server, versions 5.0, 5.5

SYMPTOMS

Simple Mail Transfer Protocol (SMTP) messages stay in the Outgoing Messages Awaiting delivery queue until they receive a non-delivery report (NDR) for certain domains.

CAUSE

The site which the message is destined for is possibly using reverse zone lookups for security purposes. The Fully Qualified Domain Name (FQDN) of the Exchange Server computer does not match its InterNic-registered IP address; hence, the telnet session to the destination mail server is refused.

RESOLUTION

Certain mail servers require specific additional Domain Name Service (DNS) records before allowing mail transfer. A Reverse Zone record needs to be created on the DNS server responsible for the source mail server's e-mail domain.

MORE INFORMATION

You can look up the reverse routing on the following link (first find out the IP address for the Exchange Server computer):

http://network-tools.com/2/

Put the IP address in the text box, and click the DNS Records radio button. This will give the result for the reverse lookup.

Additional query words: NSLOOKUP DNS LOOKUP


Keywords          : 
Version           : winnt:5.0,5.5
Platform          : winnt 
Issue type        : kbprb

Last Reviewed: April 23, 1999