In the midst of trying to utilize processor power, I created a fault tolerant DNS server a while ago. Since then, I've been trying to add another controller for exchange. So I thought I would revert back to a single primary DNS for the meantime, and now I'm balancing on a thread.

The server I thought I uninstalled DNS, is still acting as DNS. And now the PDC does not resolve.

Can anybody walk me through, I'm overwhelmed and can't think straight. I'm afraid if anyone restarts their machine they won't have internet.

Okay, so from the beginning: I was configuring Exchange on a new server 2008. How it happened I don't know, but it started to not resolve DNS. (exclamation mark on NIC) even though everything was static. So ultimately I decided to remove the server from the problem, because I noticed DNS was in disarray if I used the DNS IP of the first server. This is when I tested with nslookup on each DNS server. I had uninstalled DNS from the second server, but nslookup was still resolving with that IP address, which has me all wound up because I don't understand. So, since the first DNS server isn't resolving, I'm assuming if the second one isn't configured right I'll loose internet. I'm just confused and don't know where to start troubleshooting.

I guess my ultimate question is how can I return and verify my original AD DC to it's DNS function?

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    I think that you need to slow down, take a breath, and re-write this question. It's very scattered, hard to follow, and some of it doesn't make sense. There is no PDC in a 2003 domain. Why do you need to add another DC to run Exchange? How did you "revert back to a single primary DNS?" etc etc. Also, the fear that if people reboot their machine, they won't have internet access is a bit irrational. If you broke something like DNS, it would manifest before they rebooted. – MDMarra Feb 21 '11 at 21:56
  • Yeah I know, Im a little nerve wracked sorry. My AD w/DNS was originally the only DNS. A while back I wanted fault tolerance in case I needed to reboot the machine during production times. Really all I did was uninstall DNS from the second server. The NS records on first server still exist. But nslookup from the first server does not resolve anywhere, nor has internet.... – Seth Feb 21 '11 at 22:24
  • What are you actually doing with nslookup? Also, You should edit your original question with these details. This is a Q&A site. Anything posted below the question is considered an answer. It's a bit different than a discussion forum. – MDMarra Feb 21 '11 at 22:44
  • Gotcha, sorry for the confusion. SRV1 and SRV2 both have their first dns addresses pointing to the other server, and second pointing to themselves. nslookup google.com will resolve on SRV1 and not SRV2. If I switch the order of DNS addresses in NIC, the outcome follows the change. nsllokup google.com with resolve on SRV2 and not SRV1 (basically, as long as nslookup is using SRV2 for the reust it works.) – Seth Feb 21 '11 at 22:46

These are some incredibly fundamental questions that are being asked. I'm not trying to be rude, but if you are having these questions about how to resolve basic DNS/AD issues in your production environment, I think that the best course of action is for you to hire a consultant to get you sorted out.

I think you've gotten such a lukewarm response because there are some serious flaws in your presentation of the issue. You're incredibly unclear about your environment, your ultimate goal, and the problem itself. You also seem to lack understanding of AD by continuing to say PDC. Another red flag is saying "Yellow exclamation mark on the NIC." We expect that issues have been troubleshot beyond "oh no, an exclamation" before they get here..

The amount of work it would take to walk you through the basics to even get to a point where you can troubleshoot your environment is significant.

tl;dr - Hire someone that can fix it.


Probably not enough here to work with. What really makes you think that the server you uninstalled DNS from is really still acting as a DNS server? Are you 100% sure it is accepting remote requests? Can you connect to it with DNS Administrator running on the other server? Maybe just some of your clients still have it listed as a potential DNS server because you haven't waited long enough after removing it for them to receive the updated information?

  • Well, I run nslookup from the second server and it resolves fine(showing it's IP). From the PDC it does not resolve and has no internet... Im a little weary of restarting DNS service on serv1 but I would suppose I need to.. – Seth Feb 21 '11 at 22:21

Assuming you have the servers configured with fixed IP addresses, as is normal practice, you may want to check that you have the correct DNS server settings in there. It's one of those little steps that often get overlooked when making changes elsewhere.


As a start, point each server to itself for primary DNS. Next, are your DNS zones AD integrated? Do you have forwarders or root hints configured on SRV1 and/or SRV2?


Well as odd as it is, my firewall was causing the hang up. A reboot cleared it up. Thank you everyone for your input.

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