Multihomed PDC Causes Browsing Problems

by Wayne Maples [Published on 20 April 2004 / Last Updated on 20 April 2004]

On a multihomed primary domain controller, you can experience browsing problems and NetBIOS name resolution errors. This occurs because each browser service bound to each interface operates independently. The PDC exchanges lists with the master browser on each network. The browser service does not merge the browse list for separate networks. Applications on the PDC using NetBIOS name resolution or browser services may be incomplete.

When browsing does not work on a multihomed computer, the transport that did not work can be identified in Event Viewer by locating text similar to this:

The browser was unable to retrieve a list of servers from the browser master on the network \\

-or-

The browser service has failed to retrieve the backup list too many times on transport of .

The UnboundBindings parameter can be used to prevent the PDC from gathering a browse list from each interface. However, in a WINS environment where WINS provides the IP address for the master browser to find the PDC, there is no way of guaranteeing that the correct interface is chosen. Broadcasts may go to the unbound interface causing additional problem. This WINS side-effect cannot be overcome with Windows NT 4.0.

To guarantee that it can merge a single, domain-wide list, the PDC must not be a multihomed computer.

On a multihomed PDC running WINS, all WINS entries should have the IP address of the one network adapter that has the browser service enabled.

To enable the UnboundBindings parameter :

Hive: HKEY_LOCAL_MACHINE
Key: SYSTEM\CurrentControlSet\Services\Browser\Parameters
Name: UnboundBindings
Type: REG_MULTI_SZ
Value: NetBT_network adapter name NIC(s) you want to unbind

You can determine the network adapter names by issuing command:

net config rdr

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