Monday, October 23, 2006

More NetBIOS woes

A Windows XP computer in our network exhibited a strange problem. It could connect to a network share via remote server's NetBIOS name (e.g. \\server\share), but not fully-qualified DNS name (e.g. \\server.domain.com\share). This had all sorts of interesting consequences. For one, group policy failed to apply to this computer, because it needs to access the group policy files on the domain controller's SYSVOL share via the domain's DNS name. The event log showed an error like this: "Windows cannot access the file gpt.ini for GPO CN={Policy GUID},CN=Policies,CN=System,DC=domain,DC=com The file must be present at the location \\domain.com\Policies\{Policy GUID} (Network path not found) Group Policy processing aborted". Of course it was failing because it could not access the domain controller via the \\domain.com DNS name. This group policy failure in turn prevented the computer from receiving updates from the local WSUS server, and so on.

As it turned out, the problem was that TCP/IP NetBIOS Helper Service was not running. Starting the service resolved the problem. Once again, NetBIOS is a must.

A particularly bad thing about the TCP/IP NetBIOS Helper Service is that one cannot force it to start via group policy. If the service is not running on a computer, group policy will not apply to this computer, as my example demonstrates.

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