AFD.SYS driver and X.400 connector interoperability

[This topic is intended to address a specific issue called out by the Exchange Server Analyzer Tool. You should apply it only to systems that have had the Exchange Server Analyzer Tool run against them and are experiencing that specific issue. The Exchange Server Analyzer Tool, available as a free download, remotely collects configuration data from each server in the topology and automatically analyzes the data. The resulting report details important configuration issues, potential problems, and nondefault product settings. By following these recommendations, you can achieve better performance, scalability, reliability, and uptime. For more information about the tool or to download the latest versions, see "Microsoft Exchange Analyzers" at https://go.microsoft.com/fwlink/?linkid=34707.]  

Topic Last Modified: 2009-08-31

The Microsoft® Exchange Server Analyzer Tool reads the following registry entry to determine the version of Microsoft Windows® running on the Exchange Server computer:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\CurrentVersion

A CurrentVersion value of 4.0 indicates that the Exchange Server computer is running on Microsoft Windows NT® Server 4.0. A value of 5.0 indicates that the Exchange Server computer is running Windows 2000 Server and a value of 5.2 indicates the Exchange Server computer is running Windows Server™ 2003.

The Exchange Server Analyzer also queries the Win32_ComputerSystem Microsoft Windows Management Instrumentation (WMI) class to determine the following:

  • If the NumberOfLogicalProcessors property exists in WMI, the Exchange Server Analyzer determines the current value for NumberOfLogicalProcessors. NumberOfLogicalProcessors returns the logical processor count in the computer. This property is available in Windows Server 2008. By default, NumberOfLogicalProcessors is not available in Windows Server 2003. The hotfix that is mentioned in Microsoft Knowledge Base article 932370, "The number of physical hyperthreading-enabled processors or the number of physical multicore processors is incorrectly reported in Windows Server 2003" (https://go.microsoft.com/fwlink/?linkid=3052&kbid=932370) adds the NumberOfLogicalProcessors property to Windows Server 2003.

  • If the NumberOfLogicalProcessors property does not exist the Exchange Server Analyzer determines the current value for NumberOfProcessors. In Windows Server 2008, NumberOfProcessors only returns the number of physical processors. By default, in Windows Server 2003, NumberOfProcessors returns the number of logical processors.

The returned value represents the number of processors installed on the computer. These processors include both physical processors and logical processors. A physical processor can be split into two logical processors by using hyper-threading technology from Intel.

The Exchange Server Analyzer also reads the following registry entry to determine whether the Exchange Server is a bridgehead for an X.400 connector:

HKLM\SYSTEM\CurrentControlSet\Services\MSExchangeMTA

Finally, the Exchange Server Analyzer queries the CIM_Datafile Windows Management Instrumentation (WMI) class to determine the value of the Version key for a file named Afd.sys.

The Exchange Server Analyzer displays a warning if the following conditions are true:

  • The Exchange Server computer is running on Windows Server 2000.

  • The number of logical processors is greater than 1.

  • The Exchange Server is a bridgehead for an X.400 connector.

  • The value of the Version key for WINDOWSPATH%\\system32\\drivers\\afd.sys is in the range of 5.0.2195.7036 and 5.0.2195.7060.

This warning indicates that the version of Afd.sys installed on the server may cause mail flow issues with X.400 connectors homed on this server.

To resolve this problem, obtain the update referenced in Microsoft Knowledge Base article 904712, "Mail delivery is slower than expected, or mail delivery stops, on an X.400 connector to a remote site in Exchange Server 5.5" (https://go.microsoft.com/fwlink/?linkid=3052&kbid=904712).