nt4 backup domain controller

gebigler used Ask the Experts™
We have an nt4 domain controller that is about ready to die.  It is on subnet .20.  We want to build an nt4 BDC, but we're at another location and our subnet is .10.  We're creating the nt4 box from scratch.  When installing nt4 server software, it sees the network adapter and the adapter psses the test, but when it comes time to sign on we get the message "Unable to find domain controller".  All cables, etc are working.  We've tried several and we're able to connect a laptop on the system.  

Can a BDC be created on a different subnet?  We filled out the correct DNS, WINS, etc. in setup.

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To answer your question, yes a BDC can be on a different subnet. Can the .20 and .10 subnet communicate with each other?


Yes, they communicate all the time.  Our main data center is in Indy on .20.  We are in chicago and our PCs are on .10.  

we have DHCP on .10 and .20
WINS and DNS are on .20 only.
Could it possibly be a firewall issue or are the two subnets wide open to each other?


They're wide open.  
Can you ping the PDC from the BDC?


No, we can't get past the installation of NT4 Server.  At the end of the install it asks for sign-on info and says it can't find the domain.  
Take a laptop and assign it the same IP that the BDC would have and see if you can ping the PDC across the network.


Yes, I can ping.  
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Your WINS infrastructure is okay?
You're using the correct NetBIOS name to join the domain ("echo %userdomain%" in a command prompt on a domain member)?
Can you resolve the the domain master browser and the DC list from the .10 network?

NBLookup.exe command-line tool
NetBIOS Suffixes (16th Character of the NetBIOS Name)

What's the PDC? Still NT4 or is that a W2k3 AD running in mixed mode?
If it's an NT4 domain: try to install a stand-alone NT4 on that machine (no need to join it to the domain), then check if the NIC works *before* applying SP6a. If it doesn't work, you won't be able to install a BDC directly in that hardware configuration.
That would leave you with two options:
- install a (temporary) NIC that works with NT4
- install a member server, apply SP6a (assuming the NIC works under SP6a), the use UPromote to turn the member server into a DC.
UPromote: Promote your NT Server to a Domain Controller
If it's an AD domain, you need to pre-create the computer account (in the Domain Controllers OU) and check the "Pre-Windows 2000 DC" box during the creation.
It looks like it's a driver issue.  We can't get to a command prompt because we can't even finish the installation.  

For a workaround, we've created the NT4 BDC on MS Virtual PC 2007. Since we're using VMWare (which doesn't support NT4), these are the next steps to get everything back on VMWare.  

1.  Promote VPC BDC to PDC
2.  Upgrade to 2000 AD
3.  Create 2000 box on VMWare
4.  Transfer roles to server on VMWare

I'm going to close this one.  Thanks!


Using MS Virtual PC as an intermediate box rather than trying to get the physical server to work has solved our issue.  

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