Microsoft Exchange and Blackberry Server Specialists


If you have replaced a server with one of different name, but fear that applications or users may still be using the old NETBIOS name, then you can configure a NETBIOS alias. This will mean the new server will also respond to the old name.

A good example of when this could be useful is when a replacement Exchange server as been deployed, but there is a script used for the automatic configuration of Outlook, or you cannot be guaranteed that all Outlook clients have connected and been redirected to the new server.

To configure a NETBIOS Alias, you need to make a change to the registry.


Ensure that you have removed all references to the old server before continuing. If this is Exchange for example, the old server needs to have been removed correctly, otherwise you will have a confused Exchange organisation which may try and replicate traffic to itself! The old machine needs to have been removed from the domain and either had its name changed, or wiped, so that another machine cannot come up with the same name.

Registry Key

The key is at this location.


Add a new REG_SZ value with the name of "OptionalNames". For the string and the name of the server name that you want this machine to respond to : "OLD-SERVER". No domain information - so not example.local etc.

If you need to have multiple names, for example after a server consolidation, then use the type REG_MULTI_SZ instead.

After making the change, reboot the machine.

Don't forget DNS!

You should also make an entry in your Active Directory DNS for this name, so that the FQDN resolves to the replacement server.
That would be a new A record (if static IP address) or CNAME (if dynamic).

For an A record it would be OLD-SERVER and would have the IP address of the new replacement server.

For a CNAME, it would be called OLD-SERVER and would have the fully qualified name of the new server (new-server.example.local).