Article ID: 161778 - View products that this article applies to.
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SNA Server client users may be unable to connect over TCP/IP sockets to the SNA Server when running on a multi-homed computer running Windows NT Server 4.0. This problem may occur after initially installing SNA Server, or after upgrading a working SNA Server system from Windows NT Server 3.51 to Windows NT Server 4.0.
SNA Server client computers running either Windows 3.x or Windows 95 may receive the following errors when attempting to open a session:
NOTE: A server that has the TCP/IP protocol bound to more than one network adapter is referred to as "multi-homed." Each TCP/IP adapter binding is configured with a unique IP address connected to different logical subnets.
When SNA Server initializes, the first TCP/IP address returned by Windows sockets is advertised to SNA Server TCP/IP client computers over their "sponsor" connection. This TCP/IP address may be for an address on a disparate network from the client computer, or have an address that the client computer's default gateway does not know how to route.
This was not a problem under Windows NT Server 3.51 because the order of the TCP/IP addresses could be controlled by the TCP/IP protocol binding order within the Bindings dialog box (accessed in Control Panel Network).
Under Windows NT Server 4.0, the internal order of TCP/IP networks is determined by the order that TCP/IP initialization occurs over the network adapters. Therefore, there is no way to directly control the order that the TCP/IP addresses are registered on the SNA Server.
To resolve this problem, obtain the hotfix mentioned below. This update allows the administrator to specify which IP address should be advertised to the SNA client computers in the following registry entry:
where the default is 0. If there are two different TCP/IP addresses configured for this server, try setting the Network to "1."
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\SnaBase \Parameters\SnaTcp\ Network:REG_DWORD:<network number>
Note that this registry entry is already supported by SNA Server 3.0.
Microsoft has confirmed this to be a problem in SNA Server versions 2.0, 2.1, 2.11, and 3.0. This problem was corrected in the latest SNA Server version 2.11 U.S. Service Pack. For information on obtaining this Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces):
S E R V P A C K
Article ID: 161778 - Last Review: January 16, 2015 - Revision: 4.0