Microsoft KB Archive/137901

= SNA Server Event 563 and Win 3.x Client Application Problems =

Article ID: 137901

Article Last Modified on 11/19/2003

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APPLIES TO


 * Microsoft SNA Server 2.1, when used with:
 * Microsoft Windows NT 4.0
 * Microsoft SNA Server 3.0, when used with:
 * Microsoft Windows NT 4.0

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This article was previously published under Q137901





SYMPTOMS
The following symptoms can occur when 15 or more SNA Servers are installed within a single Windows NT domain and Windows 3.x clients are being used:  The 3270 applet may fail to start and report "DL-BASE not initialized." If you are using Wall Data Rumba, Rumba 3270 may fail to start and display the Interface Not Found message. Clients that open an SNA application session may experience long delays before receiving a host sign-on screen. The Windows NT application event log will include:

Event ID: 564

Description: Failed to initialize exit list processing, rc = 563

Event ID: 563

Description: The service table is full: too many network resources active.

NOTE: The SNA client reports Event 563 to the server, so it's the client's internal "service table" that is full, not the server's.



CAUSE
The SNA Server Windows 3.x client software supports sessions through multiple SNA Servers. However, if there are more than 14 SNA Servers currently running in the SNA Server domain, Win 3.x clients begin experiencing these problem due to an internal limit within the SNA Server Windows 3.x client service table. The service table is used by the SNA Server client to internally manage the SNA client resources being used on the client machine.

The SNA Server Win 3.x client service table contains 32 entries:
 * Two "overhead" entries (one for the sponsor connection [sponap] and one entry for WNAP).
 * One entry for every SNA Server service currently running in the domain.
 * One entry for every SNA Server configuration server (snabase) running in the domain (i.e. primary and backup servers).
 * One for each active Windows process which uses the SNA Win 3.x client API interfaces (i.e. the 3270 and 5250 applets each take one entry).
 * One for every "otherservers" entry configured on the client machine.
 * One for every invokable TP registered on the client machine.

If "otherserver" and APPC TPs are not being used, and you want to run a 3270 emulation product on the client, the maximum number of SNA Server config servers in the domain is (32 - 3 = 29 % 2) = 14. If more than 14 SNA servers are running in the domain, the above errors will be logged and the user will not be able to run an emulator on the SNA Server Win 3.x client machine.



RESOLUTION
Microsoft has updated the following files to correct this problem:

\WNAP.EXE

WINDOWS\SYSTEM\WDMOD.DLL

NOTE: These files are applied to the SNA Server Windows 3.x client, not the SNA Server.

The update to the SNA Win 3.x client software limits the number of configuration servers kept in the service table to 2 entries. This extends the theoretical number of SNA Servers supported in a domain to 27. However, Microsoft strongly recommends that SNA Server 2.11 be deployed and the subdomain feature implemented, allowing SNA Servers to be separated into logical groups within a Windows NT domain. Using the subdomain feature, the client users would connect only through one group of servers at a time. See the SNA Server 2.11 Readme file for more information about the subdomain feature.



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

Additional query words: 2.00 2.10 2.11 prodsna session drop hang

Keywords: kbbug kbfix KB137901

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