Q178493

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page	Q178493: SNA Server Status Shows "Off Line" Even Though It's Active	/kb/178/Q178493/

Q178493: SNA Server Status Shows "Off Line" Even Though It's Active

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Article: Q178493
Product(s): Microsoft SNA Server
Version(s): WINDOWS:3.0 SP2,4.0
Operating System(s): 
Keyword(s): 
Last Modified: 13-JUN-2001

-------------------------------------------------------------------------------
The information in this article applies to:

- Microsoft SNA Server, versions 3.0 SP2, 4.0 
-------------------------------------------------------------------------------

SYMPTOMS
========

After upgrading to SNA Server 3.0 Service Pack 2, or upgrading to or installing
SNA Server 4.0, SNA Manager may show the SNA Server (or TN3270, TN5250 or Print
Service) status as "Off Line" even though the service(s) may be running
correctly.

The onset of the "Off Line" status normally coincides with an access violation in
the SNA Manage Agent service (mngagent.exe), though sometimes the service does
appear to be running, the service fails to stop. When the service fails with an
access violation, the following symptoms occur:

- The SNA Manage Agent service may no longer be running

- The following entry may appear in the <ntroot>\drwtsn32.log file:

 Application exception occurred:
         App: exe\mngagent.dbg (<process id>)
        Exception number: c0000005 (access violation)

 [...]

 function: RtlDestroyHeap
       77f7d339 83c40c           add     esp,0xc
       77f7d33c 57               push    edi
       77f7d33d e83af00000       call    RtlpNtEnumerateSubKey+0x312a 
       77f7d342 c6451400         mov     byte ptr [ebp+0x14],0x0      
       77f7d346 8b4d08           mov     ecx,[ebp+0x8]          
       77f7d349 0fb707           movzx   eax,word ptr [edi]         
       77f7d34c 294128           sub     [ecx+0x28],eax         
       77f7d34f 8b4e08           mov     ecx,[esi+0x8]          
       77f7d352 8b460c           mov     eax,[esi+0xc]          
       77f7d355 3bc8             cmp     ecx,eax
  FAULT ->77f7d357 8908             mov     [eax],ecx 

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

  Function Name
  ntdll!RtlDestroyHeap 
  ntdll!LdrGetDllHandle 
  ntdll!RtlAllocateHeap 
  msvcrt!realloc 
  ws2_32!getservbyname 
  ws2_32!gethostname 
  snaip!BuildNosBlock  
  snadmod!BuildActiveNosBlocks  
  snadmod!SendDatagramTo  
  snamanag!SendDomainMailslot  
  snamanag!SNAStopService  
  mngsna!CNodeServe::OnCommand  
  mngbase!CNotifyQueue::Dispatch  
  mngbase!CNotifyQueue::ProcessWait  
  mngsna!DoMngSna

CAUSE
=====

In some cases, the SNA Manage Agent was not allocating sufficient memory to hold
management status information, causing internal buffers to be overwritten. This
problem was causing memory heap corruption within the Manage Agent service which
could cause the service to deadlock or fail with an access violation.


STATUS
======

Microsoft has confirmed this to be a problem in SNA Server 3.0 Service Pack 2
and 4.0. This problem was corrected in the latest SNA Server versions 3.0 and
4.0 U.S. Service Packs. For information on obtaining these Service Packs, query
on the following word in the Microsoft Knowledge Base (without the spaces):

  S E R V P A C K

Additional query words:

======================================================================
Keywords          :  
Technology        : kbAudDeveloper kbSNAServSearch kbSNAServ400 kbSNAServ300SP2
Version           : WINDOWS:3.0 SP2,4.0
Issue type        : kbbug
Solution Type     : kbfix

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