FIX: SNA applications that use single sign-on may stop responding when HAC becomes unavailable (326224)


The information in this article applies to:

  • Microsoft SNA Server 4.0
  • Microsoft SNA Server 4.0 SP1
  • Microsoft SNA Server 4.0 SP2
  • Microsoft SNA Server 4.0 SP3
  • Microsoft SNA Server 4.0 SP4
  • Microsoft Host Integration Server 2000
  • Microsoft Host Integration Server 2000 SP1
This article was previously published under Q326224

SYMPTOMS

An SNA application, such as a 3270 or 5250 emulator, that is configured to use Single Sign-On (SSO), may stop responding (hang) when the application tries to connect to a host session. When this problem occurs, the 3270 or 5250 emulator typically shows a blank display window after the connection to the host session is initiated.

SNA applications that have existing host sessions are not affected when this problem occurs.

CAUSE

If a Host Account Cache (HAC) database that is being used by the SNA Server service for SSO account lookups becomes unavailable, a deadlock can occur that prevents the SNA Server service from locating another HAC database.

SNA applications that use SSO stop responding while the SNA Server service is in this deadlock state because the account lookups cannot be completed.

RESOLUTION

SNA Server 4.0

A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next Microsoft SNA Server version 4.0 service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question. The English version of this fix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.
   Date         Time   Version    Size     File name
   --------------------------------------------------
   15-Jul-2002  12:32  4.0.0.606  138,848  Snarpc.dll

Note Because of file dependencies, the most recent fix that contains the preceding files may also contain additional files.

Host Integration Server 2000

Service pack information

To resolve this problem, obtain the latest service pack for Host Integration Server 2000. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

328152 How to obtain the latest service pack for Host Integration Server 2000

WORKAROUND

To resolve this problem, restart the SNA Server service on the SNA Server or Host Integration Server 2000 through which the SNA application is trying to connect.

STATUS

SNA Server 4.0

Microsoft has confirmed that this is a problem in Microsoft SNA Server version 4.0, 4.0 SP1, 4.0 SP2, 4.0 SP3, 4.0 SP4.

Host Integration Server 2000

Microsoft has confirmed that this is a problem in Microsoft Host Integration Server 2000 and Microsoft Host Integration Server 2000 SP1. This problem was first corrected in Host Integration Server 2000 Service Pack 2.

MORE INFORMATION

For more information about how the SNA Server service locates a Host Account Cache database to use for account lookups, click the following article number to view the article in the Microsoft Knowledge Base:

248479 Host account database location for single sign-on

If the HAC database that is being used for account lookups becomes unavailable, the SNA Server service detects this, and then contacts the master HAC database to locate another HAC database to use for account lookups. For more information about other issues related to SNA applications and SSO problems, click the following article numbers to view the articles in the Microsoft Knowledge Base:

321245 3270 emulators and LUA applications stop responding when they use the single sign-on feature

319419 Unable to log on to host computer when you use 3270 single sign-on

313202 SSO fails if attach message does not contain LUWID or other subfield

Modification Type:MajorLast Reviewed:11/29/2005
Keywords:kbBug kbfix kbQFE KB326224
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