Topic Last Modified: 2005-11-18

The Microsoft® Exchange Server Analyzer Tool reads the /LM/SmtpSvc/<SMTP virtual server instance>/MaxSessionSize property in the Internet Information Services (IIS) metabase to determine if its value matches the configured value for the msExchSmtpMaxSessionSize attribute in the Active Directory® directory service.

If the Exchange Server Analyzer finds that the values do not match, a warning message is displayed.

If the value in the IIS metabase does not match the value in Active Directory, it could indicate a problem with Active Directory replication or a problem with the Directory-service-to-Metabase (DS2MB) replication component in Exchange.

The function of the DS2MB process is to transfer configuration information from Active Directory to the local metabase. This configuration is stored in the local metabase instead of the registry for performance and scalability reasons. In Exchange 2000 Server and Exchange Server 2003, all of the Internet protocols (SMTP, NNTP, POP3, IMAP4, and HTTP) run as components of IIS.

Every 15 minutes, the DS2MB process copies entire subtrees from Active Directory without changing the shape of the subtree. This is a one-way write from Active Directory to the metabase; the metabase never writes to Active Directory.

Both the MaxSessionSize property and the msExchSmtpMaxSessionSize attribute use a default setting of 0, which means that there are no imposed session size limits. If the MaxSessionSize property and the msExchSmtpMaxSessionSize attribute do not have the same value, it means that Active Directory and the IIS metabase are not in sync. If the problem is caused by a failure of the DS2MB process, you can correct the problem by following the procedure below for the version of Exchange Server you are running. If the problem is caused by a partial or complete failure of Active Directory replication, you can use the Active Directory Replication Monitor utility (ReplMon.exe) to check the health and status of Active Directory replication. ReplMon can be found in the Microsoft Windows® Support Tools on the Windows Server™ 2003 CD-ROM.

To correct this error on Exchange Server 2003

  1. Check for the presence of application event log entries with a source of MSExchangeMU. If DS2MB fails, it will log an event on Exchange Server 2003.

  2. If you do not see any DS2MB failures, use ReplMon to diagnose Active Directory replication. Pay particular attention to the global catalog servers that are being used by your SMTP virtual server.

  3. If you do see DS2MB failures, or after you have eliminated or resolved any problems with Active Directory replication, restart the Exchange System Attendant service.

To correct this error on Exchange 2000 Server

  1. Use ReplMon to diagnose Active Directory replication. Pay particular attention to the global catalog servers that are being used by your SMTP virtual server.

  2. After you have eliminated or resolved any problems with Active Directory replication, restart the Exchange System Attendant service.

For more information about the reverse DNS lookup feature in Exchange, see the Microsoft Knowledge Base article 297412, "The 'Perform Reverse DNS Lookup for Incoming Messages' Option Is for Host Name Resolution" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=297412).

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

For more information about Active Directory replication, see the Knowledge Base article 232072, "Initiating Replication Between Active Directory Direct Replication Partners" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=232072).

For more information about the DS2MB process, see the Knowledge Base article 240105, "XGEN: General Information on Directory Service/Metabase Synchronization in Exchange 2000 Server" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=240105).