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Mixed Mode Domain Name?

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by bmyers 2 views

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A puzzling question: I recently upgraded my WinNT 4 domain to Win2000. The upgrade was successful and I currently have a mixed mode network with two W2K DC's and a WinNT BDC. I have WinNT, Win98 and W2K clients. DNS appears to be functioning properly and records are being dynamically updated OK. I have WINS and DHCP running. The Prior NT Domain name was/is a three letter name: XXX. The W2K domain name is: xxxxxxxx.com. The pre-W2K computers log on fine using old domain name XXX. The W2K logon fine too, using old domain name XXX. Should'nt the W2k Machines logon with xxxxxxxx.com at the logon screen? I try to "rejoin" these W2K machines to the the xxxxxxxx.com domain, but it defaults back to the old XXX domain name. Network Name informationreports domain as xxxxxxxx.com, but logon screen still is XXX.

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by timwalsh

Believe it or not everything is actually working as designed.

To provide backward compatibility with pre-Win2K clients, AD sets up both an AD domain name (which follows the DNS domain naming format - abc.com) and a NetBIOS domain name (which follows the format you are used to - ABC). In a clean install of Win2K the NetBIOS domain name will default to the part of the AD domain name prior to the period (AD domain - abc.com; NetBIOS domain - ABC) and in fact can be changed to anything you want.

When you migrate from NT4 to Win2K, this behavior is different. You will still have a NetBIOS domain name, however, this will be the same as your NT4 domain name and can't be changed regardless of what your AD domain name is (AD domain - xyz10.com; Former NT domain - ABC; NetBIOS domain - ABC).

The key here is that, it is the NetBIOS domain name that shows up in the Log-on screen regardless of the client. This behavior is goes even deeper. If you try to join a computer running a pre-Win2k OS (WS or Server), and enter an AD domain name to join, you will get an error message to the effect that you entered an invalid doamin name. The AD format is simply not recognized, only the NetBIOS format. To make things even more confusing,when joining a Win2K or later client to an AD domain, you must enter the AD domain name because the NetBIOS domain name won't be recognized. BTW, this behavior also exists regardless of whether the domain is operating in mixed mode or not.

Hope this helps clear up the confusion.

by curlergirl

Tim gave a great answer - he should get the points. Just an added clarification - your DNS and AD domain names are generally the same - abc.com - while the NetBIOS domain name can be different. As Tim said, in a migrated or upgraded domain, you might have (as I do in my own company) a NetBIOS domain name and a DNS/AD domain name that are completely different. Or even in a newly installed Win2K domain, you can choose to do this. Like you, I thought that the new Win2K and XP machines should logically be logging on to the DNS/AD domain, because that's what you actually see if you go to the properties of My Computer and look at the domain membership information. Nevertheless, you will still see (correctly) the NetBIOS domain name instead in the login screen. Go Figure!!

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