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Adding a New Subnet

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by russellrl2

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I work for a department in a university so my IP address/subnets are given to me from the main IT people. We did an upgrade to our switches and our other building was given a new subnet. I added the subnet in Active Directory Sites and Services. I entered the new IPs in the DNS server. I can access the internet alright but I cannot join the domain. It cannot find a domain controller. What am I missing?

10 replies

by jacobgin1

this is obvious as the subnet is outside the servers range, the other pc will not be able to communicate with server. u will require a router to make both the subnet to talk to each other. a work around is to have a pc with 2 network cards and to give one subnet in one card and the other on the other card. the gateways should be made the oposite. this will help the networks to talk to each other but throuth this pc. the traffic on this pc's cards will be high and i recomment putting a intel pro1000S network cards. this will reduce the load on the processor of the pc.

by lowlands

Did the IP's for the DC's change?
Are you having issues joining PC's to the domain or servers?

It sounds like you do have DNS issues, a few things to look at.

- if the IP for the DNS server changed, make sure this is reflected on the workstations you are trying to join to the domain.
- if you changed the IP's for any of the DC's, verify if these changes are reflected in the AD specific DNS records. A good tool to troubleshoot is NLTEST

by russellrl2

I will award the points to you based on it being a DNS issue. For some reason I cannot ping the DNS server from the new subnet but can ping all other servers. I created a secondary DNS server on a domain controller and I was able to join the domain. At this point we still cannot understand why the new subnet cannot talk to the primary DNS server.

by exnn

Do DC's belong to both subnets?
Can you ping them from any client?
Flush DNS entries from clients (ipconfig /flushdns)

by burcjo

The problem may be that it just can't connect to a global catalog server from over a slow link, or perhaps traffic just can't get to the server from the new subnet. I'm guessing the problem is in the switches and routing that's not happening or traffic not being allowed because of VLAN configurations.

by russellrl2

The main IT guys say there are no restrictions from the networks as to who can get in or out of those networks. I did notice that I can ping successfully the new subnet gateway and computers from a PC on the original network. However, I cannot ping these from our servers. That would explain why I can't join the network. So what is missing on the server side?

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