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Migrating DNS server to new subnet

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Last Modified: 2012-05-10
I have a current windows 2003 AD DNS server on 10.2.1.x

We are bringing up new Windows 2008 R2 AD DNS servers on 10.10.55

I have alot of apps that possibly are hardcoded for 10.2.1.x, so I want to be able to have my new DNS server serve them as well. The server has 2 NIC's but last time I tired to have 2 seperate nics on 2 different subnets with 2 different gateways things did not go so well. Can anyone help me think outside the box? We dont currently have any Layer 3 switches in place, so NATing isnt that easy.


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Commented:
Not clear whether these servers are just DNS servers or are AD DCs as well?

If DCs, then you can get trouble with multiple NICs but these can be sorted by altering the binding priorities.  If they are not DCs, then dual homing DNS servers should work but you should NOT have multiple default gateways - just one for when that server needs to get at networks other than the two they are on (10.2.1.0 and 10.10.55.0)

If these servers are both in the same AD forest, then replication will happen automatically.  Otherwise they will need configuration to replicate.  Are you comfortable about this?

Author

Commented:
The servers ARE AD DC's as well.

Author

Commented:
Single forest / single domain AD setup.

Commented:
Good.  That solves the replication problem.  Try again with two NICs; one on each of the networks.  Only have one NIC (the one on 10.10.55.0 with a valid default gateway.  Leave it blank on the other.

Now go to Network Sharing Center in Control Panel /' Change Adapter Settings.  Press Alt, then choose Advanced / Advanced Settings and check that File and Printer Settings and Client for Microsoft Networks only has check mark for the NIC on 10.10.55.0 network under Adapters & Bindings.  That will disable the NIC on 10.1.2.0 subnet from trying to serve MS network stuff.

I would expect this to work but am not going to be too assertive about it so make a note of the settings before you change it in case you need to roll back

Author

Commented:
So excuse my lack of knowledge here, but if the 2nd NIC (10.2.1.0) doesnt have a Default Gateway, how will the traffic A. get to it,, and B. know where to go if it gets a DNS request on 10.2.1.0


Commented:
Traffic will get to the old DNS server through the new server which knows about both of your networks AND has a default gateway to the outside world.  You will set a default gateway on the old DNS server that is the address of the NIC on the new server that's connected to 10.1.2.0 and the old DNS server will get back to the workstations again via the new server.  It will do the routing.  I think it will do this without having to install RRAS but I'm prepared to be persuaded otherwise
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Commented:
Oh, sorry - I got the wrong end of the stick.  I thought you just wanted the hard-coded workstations to be able to get to the old server when they're on their new network.  Scrub everything I've said!  So you want your new server to respond to queries sent to BOTH networks.  

Having misunderstood once, can I clarify whether these queries will be coming from other machines or from applications running on one of the servers?  If the former, which network are they on - and will they be migrating?  If the latter, I assume they will be migrated to the new server since you want to get rid of the old server.  Is that right?
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Commented:
No solution was posted so I am closing the question
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