Microsoft KB Archive/168963

From BetaArchive Wiki
Knowledge Base

Article ID: 168963

Article Last Modified on 11/19/2003


  • Microsoft SNA Server 3.0, when used with:
    • Microsoft Windows NT 4.0
  • Microsoft SNA Server 3.0 Service Pack 4, when used with:
    • Microsoft Windows NT 4.0

This article was previously published under Q168963


The SNA Server service (Snaservr.exe) may fail unexpectedly with an access violation, causing the following entry to be logged in the <Ntroot>\Drwtsn32.log file, indicating an access violation in function "s1plgrsp":

   Application exception occurred:
      App: snaservr.DBG (<process ID> )
      When: <date> @ <time>
      Exception number: c0000005 (access violation)

   [ data omitted ]

   State Dump for Thread Id 0xa8

   eax=00cc806c ebx=00ce3b3c ecx=00040004 edx=012623e8 esi=00000000
   eip=003c93d5 esp=002bff0c ebp=00106be8 iopl=0         nv up ei pl nz na
   po nc
   cs=001b  ss=0023  ds=0023  es=0023  fs=0038  gs=0000

   function: s1plgrsp
   [ data omitted ]
      003c93cb c6401600         mov     byte ptr [eax+0x16],0x0
      003c93cf 8b07             mov     eax,[edi]
      003c93d1 c6401701         mov     byte ptr [eax+0x17],0x1
   FAULT ->003c93d5 0fbf4604         movsx   eax,word ptr [esi+0x4]
      003c93d9 03c6             add     eax,esi

   *----> Stack Back Trace <----*

   FramePtr ReturnAd Param#1  Param#2  Param#3  Param#4  Function Name
   00106be8 03830000 01030aea 00000000 01d70000 00050012 snaservr!s1plgrsp


A 3270 emulator was sending an invalid STATUS ACKNOWLEDGE (STATUS ACK) message to the SNA Server computer; the message contained no element data. A memory access violation occurred when SNA Server computer attempted to access this non-existent element data.


Microsoft has confirmed this to be a problem in SNA Server 2.11 and 3.0

A supported fix for SNA Server version 2.11 is now available, but has not been fully regression-testedand should be applied only to systems experiencing this specific problem.Unless you are severely impacted by this specific problem, Microsoftrecommends that you wait for the next Service Pack that contains thisfix. Contact Microsoft Product Support Services for more information.

This problem was corrected in the latest SNA Server version 3.0 U.S. Service Pack. For information on obtaining this Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces):



An update to SNA Server 2.11 (post Service Pack 2) and SNA Server 3.0 (post Service Pack 1) is available to correct this problem. The updated modules are:


When receiving an invalid "STATUS ACK" message from a 3270 emulator, SNA Server now checks for the presence of element data, and if not it is present, SNA Server drops the client session and logs the following new event:

Event ID: 62
Source: SNA Server
Description: Illegal STATUS ACKNOWLEDGE message received from a client.
Client Domain = <client domain>
Client User Name = <user name>
LU Name = <LU name.

An emulator has sent an invalidly formated STATUS ACKNOWLEDGE message.
The message has no element.

Contact Microsoft Technical Support.

If this event is logged, determine the emulator software and version running on the client computer and reported it to Microsoft Technical Support. This event indicates a software defect in the emulator software being used.

Keywords: kbnetwork KB168963