Q178493: SNA Server Status Shows "Off Line" Even Though It’s Active
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
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The information in this article applies to:
- Microsoft SNA Server, versions 3.0 SP2, 4.0
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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:
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Keywords :
Technology : kbAudDeveloper kbSNAServSearch kbSNAServ400 kbSNAServ300SP2
Version : WINDOWS:3.0 SP2,4.0
Issue type : kbbug
Solution Type : kbfix
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