XGEN: Exchange 2000 Server SMTP Optimized with Maximum Handle Threshold Registry Key (271084)

IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows Registry

SUMMARY

You can optimize Exchange 2000 Server computers that have large amounts of memory by raising the number of Simple Mail Transfer Protocol (SMTP) handles. If you raise the maximum SMTP handle threshold, you increase the number of messages that are opened simultaneously. This enables SMTP to process a large queue at a faster rate.

If you increase this value, you need to decrease the Max IFS Handle value to avoid running out of kernel memory in a large queue situation.

For additional information, click the article number below to view the article in the Microsoft Knowledge Base:

267551 XGEN: Modifying Exchange 2000 Server File Handle Cache Parameters

When the server becomes low on kernel memory, the system becomes unresponsive. To regain control of the server, you need to restart the server to free up the kernel memory.

MORE INFORMATION

WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

To configure the maximum SMTP handle threshold value, you need to manually add the following registry key:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\SMTPSVC\Queuing\MsgHandleThreshold

To add this registry key:

Start Registry Editor (Regedt32.exe).
Locate the following key in the registry:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services
On the Edit menu, click Add Key, and then add the following registry key:
Key Name: SMTPSVC
Class: (leave this blank)
Select the following new key in the registry:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\SMTPSVC
On the Edit menu, click Add Key, and then add the following registry key:
Key Name: Queuing
Class: (leave this blank)
Select the following new key in the registry:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\SMTPSVC\Queuing
On the Edit menu, click Add Value, and then add the following registry value:
Value Name: MsgHandleThreshold
Data Type: REG_DWORD
Radix: Decimal
Value: The default value is 1,000. It is recommended that this value not exceed 15,000.
Quit Registry Editor.