Topic Last Modified: 2006-07-07

The Microsoft® Exchange Server Analyzer Tool queries the Active Directory® directory service to determine whether the value of the ncacn_ip_tcp: string of the networkAddress attribute for the server object matches the Fully Qualified Domain Name (FQDN) in the msExchSmtpFullyQualifiedDomainName attribute from the Simple Mail Transfer Protocol (SMTP) virtual server object.

If the Exchange Server Analyzer determines that the values of these attributes do not match, the Exchange Server Analyzer displays a warning.

This warning indicates that the values of these attributes may have been manually changed and could be contribute to mail flow problems on this server.

The value of the msExchSmtpFullyQualifiedDomainName attribute specifies the FQDN for the SMTP virtual server and must be resolvable by the Domain Name System (DNS) networking protocol.

A valid DNS HOST (A) record must exist for the value of this attribute so that messaging servers that try to resolve the FQDN of the SMTP virtual server can retrieve the correct IP address and route mail appropriately.

For more information about the reverse DNS lookup feature in Exchange, see "Add a resource record to a DNS zone" (

For more information about SMTP virtual server settings, see the following Knowledge Base articles:

For more information about SMTP Service Design, see "SMTP Service Design" in the Technical Reference Guide for Exchange Server 2003 (