Microsoft KB Archive/173174

= Activating SNA DLC 802.2 Local SAP 0xC4 Fails with Error #0235 =

Article ID: 173174

Article Last Modified on 5/5/2005

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APPLIES TO


 * Microsoft SNA Server 2.11 Service Pack 1
 * Microsoft SNA Server 2.11 Service Pack 2
 * Microsoft SNA Server 4.0
 * Microsoft SNA Server 3.0 Service Pack 2
 * Microsoft SNA Server 3.0 Service Pack 3
 * Microsoft SNA Server 3.0 Service Pack 4
 * Microsoft SNA Server 4.0
 * Microsoft SNA Server 4.0 Service Pack 1
 * Microsoft SNA Server 4.0 Service Pack 2
 * Microsoft SNA Server 4.0 Service Pack 3

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This article was previously published under Q173174



SYMPTOMS
When you start the SNA Server service, the service starts but the following error message appears:

SNA Server - ERROR #0235

All SAP's failed to open, no connection is usable

Also the following events are logged in the Windows NT application event log:

Event ID: 234

Source: SNA DLC Link Service

Type: Warning

Description: Failed to open SAP 196, error (43)

Some connections may now be unavailable

EXPLANATION

The DLC (802.2) link service failed to open a service access point (SAP)

during initialization. If error code 43 is displayed, the SAP has already

been opened by another link process.

Followed by:

Event ID: 235

Source: SNA DLC Link Service

Type: Error

Description: All SAP's failed to open, no connection is usable

This problem occurs if an SNA Server 802.2 DLC link service is configured to use a local SAP address of 0xC4. This DLC SAP address is always opened by the Windows NT Hpmon.dll file (a component of the Hewlett Packard DLC- attached Network Print support), regardless of whether a network attached printer is being used.



CAUSE
When you configure a large number of SNA Server DLC 802.2 connections to the same IBM host address, a unique SNA DLC 802.2 link service must be used for each connection, where the local SAP address is incremented by 4 for each link service. For example, the first link/connection uses a local SAP address of 0x04, the second uses 0x08, the third uses 0x0C, and so on. If up to 49 802.2 DLC link services are being used, the local SNA SAP address for the 49th link/connection uses SAP address 0xC4.

However, SAP address 0xC4 is automatically opened by Hpmon.dll when the Windows NT print subsystem initializes, and it cannot be changed. This causes a conflict with the 49th SNA Server 802.2 link service/connection, leading to the above error messages.



WORKAROUND
There are two possible workarounds for this problem:
 * Skip local SAP address 0xC4. Instead of using 0xC4, use the next SAP or 0xC8.
 * Disable HPMON, if it is not being used.

The Hpmon.dll file can be renamed so that it is not loaded, assuming the Windows NT Server computer is not supporting DLC-attached HP network printers. Note that TCP/IP attached HP printers are not affected by this module, only DLC attached printers. To disable the Hpmon.dll file, perform the following procedure:
 * 1) Rename \system32\HPMON.DLL to HPMON.OLD.
 * 2) Shut down and restart the Windows NT Server computer.

Keywords: kbprb KB173174

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