Event ID: 9409 occurs every time that the Microsoft Exchange MTA Stacks service (MSExchangeMTA) starts in Exchange Server 2003

On a computer that is running Microsoft Exchange Server 2003, the following event is logged in the Application log every time that the Microsoft Exchange MTA Stacks service (MSExchangeMTA) starts:

Event source: MSExchangeMTA
Event category: Field Engineering
Event ID: 9409
Date: date
Time: time
Type: Information
User: N/A
Computer: ComputerName
Description: The Microsoft MTA registry parameter Max RPC Alloc Size is missing. The default value will be used. (BASE MAIN BASE 1) (14)

This event is logged even if you do not enable extended diagnostics logging in Exchange Server 2003.

This issue occurs because of enhanced code security that is included in Exchange Server 2003. Exchange Server 2003 includes enhanced code security to help prevent unauthorized clients from sending packets that could cause the server to allocate large blocks of memory.

Note The event ID 9409 message is an information message. This event does not indicate a problem with Exchange Server 2003.

Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall your operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

To stop this event from being logged, follow these steps:

1. Click Start, click Run, type regedit, and then click OK.
2. Locate and then click the following registry subkey:
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeMTA\Parameters
3. On the Edit menu, point to New, and then click DWORD Value.
4. Type Max RPC Alloc Size to name the new DWORD value, and then press ENTER.
5. Right-click Max RPC Alloc Size, and then click Modify.
6. Click Decimal, and then type the number of megabytes that you want to allow for the maximum RPC allocation in the Value data box.
   
   The default value for this registry entry is 100 MB. This value corresponds to the following equation:
   104857600/1024/1024 = 100 MB
   For example, to set this value to 101 MB, type 105906176 (hexadecimal value 0x6500000). This value corresponds to the following equation:
   101 * 1024 * 1024 =105906176
7. Click OK.
8. Exit Registry Editor.

The event ID 9409 message is logged on Exchange Server 2003 servers that are running the Microsoft Exchange MTA Stacks service together with a configured connector. This behavior is expected. This event is logged at all logging levels in Exchange.