DHCP not working

dynamikdynamik Banned Posts: 12,312 ■■■■■■■■■□
We're a small business that had two DCs that also provide DHCP and DNS, one was also a file server. I built a new file server and transferred the files over the weekend. Today, there are problems with network connectivity. Machines with static IPs and those with existing DHCP leases are fine. The problem is, no one can obtain a new lease. I tested this on a few machines on a few machines by trying to manually renew their lease, which left them with no connectivity icon_lol.gif

Anyway, when I checked the event logs, it said that the DHCP server (on both machines) couldn't find a DC to authorize to. I'm not sure how that would exactly work since they both run on DCs. Anyway, I manually restarted the DHCP service, and checked the logs again. Both said that they were up and running and now servicing clients. When I look at DHCP under administrative tools. It initially says "Not connected", but when I click on it, it says "Running."

I'm a bit frazzled from the whole weekend and this morning, so I'm probably just missing something obvious. Any help would be appreciated.


Both servers are authorized and have the green up arrow.

The DHCP server service is listed as "started" under services.

Client machines have normal network connectivity if I assign them static IPs. I might just go do that on the few machines have expired leases for the time being...


  • sprkymrksprkymrk Member Posts: 4,884 ■■■□□□□□□□
    Is the file server seperate from the DHCP server? Did you check the firewall on the servers?
    Can hard coded clients ping and otherwise access both servers? I can't tell if you are talking about one or both servers.

    1. Which server did you rebuild?
    2. Is DHCP running on both?
    3. Do they have conflicting scopes?
    4. Do either of the servers have 2 nics?

    Just some random thoughts....
    All things are possible, only believe.
  • dynamikdynamik Banned Posts: 12,312 ■■■■■■■■■□
    DHCP is on both domain controllers. I've disabled the firewall for testing. The file server is a separate machine with a static IP. New leases are not being distributed anymore. This has mostly affected laptop users since they're coming from home and need new IPs. I thought it was the access point at first, but a few clients with old leases haven't been able to renew, and I can't renew manually.

    I can ping and remote desktop to them from numerous other machines. Like I said, there is no connectivity problems for clients with existing leases or static configurations. They're just not handing out new leases anymore.

    I didn't rebuild either. I built a new file server and just robocopied the files over to that one. I didn't do any other configuration changes (DNS, DHCP, etc.) to the existing domain controllers. They have the same settings they've had for over two years. This is the reason I'm so confused.

    DHCP is running on both. The first scope is 100-199 and the other is a backup with just 200-250. Both DCs only have one NIC.

    I hope I run into a bunch of DNS problems as well. That way I can go over some more of my 291 material over the next few days icon_twisted.gif

    Thanks for the response.


    Here is part of the output for my DHCP log for this morning:

    50,12/10/07,07:16:54,Unreachable Domain,,domain.com,8250,
    50,12/10/07,07:17:18,Unreachable Domain,,domain.com,8250,
    24,12/10/07,08:16:19,Database Cleanup Begin,,,,
    25,12/10/07,08:16:19,0 leases expired and 0 leases deleted,,,,
    25,12/10/07,08:16:19,0 leases expired and 0 leases deleted,,,,
    24,12/10/07,10:00:48,Database Cleanup Begin,,,,
    25,12/10/07,10:00:48,0 leases expired and 0 leases deleted,,,,
    25,12/10/07,10:00:48,0 leases expired and 0 leases deleted,,,,
    24,12/10/07,11:00:49,Database Cleanup Begin,,,,
    25,12/10/07,11:00:49,0 leases expired and 0 leases deleted,,,,
    25,12/10/07,11:00:49,0 leases expired and 0 leases deleted,,,,

    I had to shut them down to hook up a new kvm this morning. It looks like the domain was unreachable when they came back online. Once people came in a report the problem, I restarted the service at 9, and it looks like it got back up and running. It looks like it was able to successfully renew an address earlier as well.
  • MishraMishra Member Posts: 2,468 ■■■■□□□□□□
    Quit robocopying your ntds.dit file!!! :)
    My blog http://www.calegp.com

    You may learn something!
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