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Article ID: 137309 - Last Review: October 31, 2013 - Revision: 3.0

 
This article was previously published under Q137309

Symptoms

This Windows NT STOP Message appears when SNA Server 2.1 or 2.11 supports users over native TCP/IP sockets.
STOP: 0x0000003f
NO_MORE_SYSTEM_PTEs

Cause

When an SNA client computer has a TCP/IP socket connection to an SNA Server, the server periodically sends a KeepAlive message to the client to speed up the detection of a lost client LAN session. SNA Server TCP/IP KeepAlive messages do not complete because the client's TCP receive window size dropped to zero. The SNA Server keeps on queuing new KeepAlive messages (even though earlier keep alive messages haven't completed) until the SNA Server runs out of system PTEs.

Resolution

WARNING: Using the Registry Editor incorrectly can cause serious, system- wide problems that may require you to reinstall Windows NT to correct them. Microsoft cannot guarantee that any problems resulting from the use of the Registry Editor can be solved. Use this tool at your own risk.

Microsoft has modified the files, SNADMOD.DLL and SNAIP.DLL, so that SNA Server does not queue a new KeepAlive until the previous one has completed. Thus, the connection is aborted after a configurable timeout. The timeout is specified in the following registry parameter:
   HKEY_LOCAL_MACHINE
     \System
       \CurrentControlSet
         \Services
           \Snabase
             \Parameters
               \SnaTcp
                 KeepAliveLimit: REG_DWORD: 0 - 0xFFFFFFFF
				
The KeepAliveLimit specifies how many WatchDogTimeouts SNA Server waits before aborting the connection. The default watchdogtimeout value is 60 seconds, though this is also configurable under:
   Hkey_local_machine
     \System
       \CurrentControlSet
         \Services
           \SnaBase
             \Parameters
               \watchdogtimeout REG_DWORD: <value>
				
If a second keepalive is sent to a client box, SNA Server now logs Event 700 to indicate this (logged only when detailed problem analysis logging is enabled). If the limit is exhausted, then SNA Server logs a 701 event at a high severity to indicate this. The client's IP address is logged in these new events.

The registry value, HardClse, controls how the connection is aborted. If the value is "yes", the connection is reset immediately and no effort is made to close the connection gracefully. The default value is "no". HardClse is found in the following subtree:
   Hkey_local_machine
     \System\CurrentControlSet
       \Services
         \SnaBase
           \Parameters
             \TcpIp
               \HardClse
				
REG_SZ: ("no" -or- "yes")

Status

Microsoft has confirmed this to be a problem in SNA Server for Windows NT. This problem was corrected in the latest SNA Server for Windows NT, 2.11 U.S. Service Pack. For information on obtaining the Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces):
S E R V P A C K

Applies to
  • Microsoft SNA Server 2.1
Keywords: 
kbnetwork KB137309
Retired KB ArticleRetired KB Content Disclaimer
This article was written about products for which Microsoft no longer offers support. Therefore, this article is offered "as is" and will no longer be updated.
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