How to disable SNA NT Client smart multihoming (234687)


The information in this article applies to:

  • Microsoft SNA Server 3.0 SP2
  • Microsoft SNA Server 3.0 SP3
  • Microsoft SNA Server 3.0 SP4
  • Microsoft SNA Server 4.0
  • Microsoft SNA Server 4.0 SP1
  • Microsoft SNA Server 4.0 SP2
This article was previously published under Q234687
Important This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows Registry

SUMMARY

SNA Clients are configured by default to use smart multihoming. When an SNA Server is multihomed, a list of all the TCP/IP addresses for the SNA Servers are passed back to the SNA Client. The SNA Client chooses the TCP/IP address which is closest to its own TCP/IP subnet or TCP/IP address. Occasionally, the best TCP/IP address is not reachable because of network design. This causes a delay in the client connecting to the SNA Server. The time delay depends upon the TCP/IP retry timers configured on the client, but should be 45 to 55 seconds assuming the retry-timer settings have not been modified from their defaults.

MORE INFORMATION

For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

182332 SNA clients experience delay connecting to multihomed server

Smart multihoming is enabled by default on all clients starting with SNA 3.0 Service Pack 2 clients.

To disable smart multihoming, the client needs to have the registry value ReadjustMultihomedAddresses (a REG_SZ) set to NO.

NOTE: This applies to SNA Windows NT Clients ONLY. Other SNA clients have no such registry value.

The above registry value is located in the following registry key:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Snabase\Parameters\SnaTcp

If smart multihoming is disabled, then the client tries all addresses in the order in which the server has passed them to the client in the Service Table.

This feature is available in the latest service pack for SNA Server version 4.0. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

215838 How to obtain the latest SNA Server version 4.0 service pack

This feature was first included in SNA Server version 4.0 Service Pack 3.
Modification Type:MinorLast Reviewed:6/5/2006
Keywords:kbHotfixServer kbQFE kbsnaonly kbFEA kbinfo KB234687
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