This article was previously published under Q187708
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A SQL Server client may not be able to connect to SQL Server in a clusterenvironment using the virtual server network name or IP address by means ofTCP/IP sockets. A typical client application will return the followingerror message:
Unable to Connect: SQL Server is unavailable or does not exist. General network error. Check your documentation. Net-Library error 10061: ConnectionOpen (Connect())
However, the same socket client can connect to the SQL Server using thenode name or address of the computer where SQL Server is physicallyrunning. Clients running named pipes do not have this problem of connectingto SQL Server through the virtual server name.
There is a known problem with Windows NT 4.0 Enterprise Edition that mayreturn an incorrect IP address under certain situations when an applicationsuch as SQL Server calls socket function gethostbyname() to retrieve thevirtual server IP address from the local node. When SQL Server is bound tothis incorrect IP address (node address), a socket client will not be ableto connect to the SQL Server through the virtual name or IP address, butcan connect to it through node name or IP address.
One way to verify whether you have run into this issue is to PING the SQLServer virtual server name from the command prompt on the node computerwhere SQL Server is currently running. If PING returns the node IP addressrather than the SQL Server virtual server IP address, then you have runinto this problem. Note that if you PING this virtual server name from aseparate network client computer, it returns the correct IP address.
To resolve this problem, obtain the latest service pack for Windows NT 4.0 or Windows NT Server 4.0, Terminal Server Edition. For additional information, click the following article number to view the article in theMicrosoft Knowledge Base:
152734 How to Obtain the Latest Windows NT 4.0 Service Pack
You can work around this problem by using named pipes for clientconnections.
Microsoft has confirmed that this is a problem in Windows NT 4.0 and Windows NT Server 4.0, Terminal Server Edition. This problem was first corrected in Windows NT 4.0 Service Pack 4.0 and Windows NT Server 4.0, Terminal Server Edition Service Pack 4.
4.00 ntee winsock connection refused failed machine mscs server cluster