Microsoft KB Archive/168815
Article ID: 168815
Article Last Modified on 10/28/2006
- Microsoft Exchange Server 4.0 Standard Edition
- Microsoft Exchange Server 5.0 Standard Edition
This article was previously published under Q168815
IMPORTANT: This article contains information about editing the registry. Before you edit the registry, make sure you understand how to restore it if a problem occurs. For information on how to do this, view the "Restoring the Registry" online Help topic in Regedit.exe or the "Restoring a Registry Key" online Help topic in Regedt32.exe.
The Microsoft Exchange Server message transfer agent (MTA) may not start; one or both of the following event ID's will be seen in the event viewer:
Event ID: 9228 Source: MSExchangeMTA Type: ERROR Category: Configuration A fatal resource limit was reached while attempting to open an association. The number of network type 2 listen control blocks requested is too high. Number requested: 2. Number configured: 1. [BASE IL MAIN BASE 1 250] (16) Event ID: 4300 Source: MSExchangeMTA Type: ERROR Category: Configuration Unable to initialize due to a bad configuration. Contact Microsoft Product Support Services. Error code=%1 [%2 %3 %4 %5] (16)
This is caused by an inadequate number of control blocks allocated to a transport stack. In the above error message, the "network type 2" refers to TP4 protocol. Two control blocks were requested; however, there is one allocated control blocks. The content of this error message may vary, dependent on the mis-configured control blocks for the network type.
Network Types Numbers Type 0x01 TCP/IP RFC 1006 Type 0x02 TP4 Type 0x03 Eicon X.25 Type 0x04 Named pipes over RAS connection Type 0x05 RPC
WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall Windows. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.
For information about how to edit the registry, view the "Changing Keys And Values" online Help topic in Registry Editor (Regedit.exe) or the "Add and Delete Information in the Registry" and "Edit Registry Data" online Help topics in Regedt32.exe. Note that you should back up the registry before you edit it.
To correct the problem, do the following:
- Start Windows NT registry editor (Regedit or regedt32).
Modify the following value to 0x2
HKEY_Local_Machine\System\CurrentControlSet\Services \MSExchangeMTA\Parameters\TP4 control blocks: Value 0x2
There must be at least two control blocks allocated to TP4 in the registry. This is true regardless of whether TP4 protocol is used or installed on the server.
The default registry value for TP4 is 0x14H or 20 Decimal.
For information about the limit on the number of allowed socket control blocks for TCP and TP4, please see the following article in the Microsoft Knowledge Base:
166602 XCON: MTA Only AllowS 64 TCP/IP or TP4 Connections
Additional query words: resource Xcon
Keywords: kbusage KB168815