TN3270 Access Violation When Using Unique Ports for Sessions

• Microsoft SNA Server, versions 3.0, 3.0SP1, 3.0SP2, 3.0SP3, 3.0SP4, 4.0, 4.0SP1, 4.0SP2

SYMPTOMS

Attempting to start the TN3270 server may result in an access violation if it has more than fifty TN3270 sessions configured to use unique TCP/IP ports.

If the Windows NT Server running SNA Server is configured with Drwtsn32.exe as the default debugger, a Drwtsn32.log will be generated when the access violation occurs.

The Drwtsn32.log may contains entries similar to one of the following if this problem occurs:

Application exception occurred:
        App: exe\tn3servr.dbg (pid=<process ID>)
        When: <date> @ <time>
        Exception number: c0000008

   [data omitted]

function: RtlRaiseStatus
[...]
FAULT ->77f88f29 8be5             mov     esp,ebp
[...]

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

FramePtr ReturnAd Param#1  Param#2  Param#3  Param#4  Function Name
00efff28 77f6cf15 c0000008 00000000 77f675ad 00098e64 ntdll!RtlRaiseStatus 
602012a0 55536021 57c08556 0102840f 15ff0000 60201050 ntdll!RtlpUnWaitCriticalSection 

Application exception occurred:
        App: exe\tn3servr.dbg (pid=<process ID>)
        When: <date> @ <time>
        Exception number: c0000005 (access violation)

   [data omitted]

function: RtlpWaitForCriticalSection
[...]
FAULT ->77f6cc66 ff4010           inc     dword ptr [eax+0x10]   
[...]

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

FramePtr ReturnAd Param#1  Param#2  Param#3  Param#4  Function Name
00d8fc18 77f67456 00095d54 01017c7e 00095d54 00084ed8 ntdll!RtlpWaitForCriticalSection 
00d8ffb8 77f04f2c 00000000 00000002 0000012e 00000000 ntdll!RtlEnterCriticalSection 
00d8ffec 00000000 00000000 00000000 00000000 00000000 kernel32!lstrcmpiW 
00000000 00000000 00000000 00000000 00000000 00000000 tn3servr!<nosymbols> 

Event ID: 902
Source: TN3270 Server
Description: Logic error in module SocketActivateEvent identified by: CouldNotFindSocket

Event ID: 902
Source: TN3270 Server
Description: Logic error in module SocketAdd identified by: NoFreeSockets

CAUSE

The TN3270 server is not correctly handling the initialization of more than 50 unique TCP/IP ports. This results in the access violations discussed above when starting a TN3270 server configured with Logical Units (LUs) using unique TCP/IP ports.

RESOLUTION

To resolve this problem, obtain the latest service pack for SNA Server version 4.0. For additional information, please see the following article in the Microsoft Knowledge Base:

Q215838 How to Obtain the Latest SNA Server Version 4.0 Service Pack

STATUS

Microsoft has confirmed this to be a problem in Microsoft SNA Server versions 3.0, 3.0 SP1, 3.0 SP2, 3.0 SP3, 3.0 SP4, 4.0, 4.0 SP1, 4.0 SP2. This problem was first corrected in SNA Server version 4.0 Service Pack 3.

MORE INFORMATION

In addition to correcting the access violations when initializing more than 50 unique TCP/IP ports, the TN3270 server has been updated to listen over a maximum of 1,000 unique TCP/IP ports. Previously, the TN3270 server could listen over a maximum of 64 unique TCP/IP ports.

With this update applied, the TN3270 can be configured to listen over port 23 (the default TN3270 port) plus an additional 999 user-defined ports.

Please refer to the on-line SNA Server Help for more details on how to configure the TN3270 server and its TN3270 LUs to use specific ports other than the default port of 23.

Additional query words:

Keywords : sna4sp3fix sna3 sna3sp1 sna3sp2 sna3sp3 sna3sp4 sna4 sna4sp1 sna4sp2
Version : WINDOWS:3.0,3.0SP1,3.0SP2,3.0SP3,3.0SP4,4.0,4.0SP1,4.0SP2
Platform : WINDOWS
Issue type : kbbug