Take the 2-minute tour ×
Server Fault is a question and answer site for professional system and network administrators. It's 100% free, no registration required.

We have a Windows Server 2003 SP2 machine that is a domain controller, DNS server, and DHCP server. (We realize that having all three roles running on the same computer is not the optimal configuration but there are no other machines available.)

There is another DNS server on the network, but this particular server is listed as the primary for client workstations. All zones are Active Directory Integrated and are configured for secure dynamic updates.

The server is the only authorized DHCP server on the network. It is enabled for Dynamic DNS updates.

We've been experiencing some strangeness. Sometimes, client workstations will lose access to the Internet. The resolution appears to be manually changing the IP address to a different one. Moreover, bad address entries are starting to appear in DHCP. We've been manually deleting them, but they keep on appearing.

This lead us to believe the problem is caused by the DHCP server. I took a look at the audit logs for DHCP. The log showed a whole bunch of Event ID error code 31: DNS Update Failed

31,07/01/09,11:47:26,DNS Update Failed,,TEST.private.local,-1,

After researching the issue, we found that if DHCP is installed on a domain controller that is also a DNS server, we should create a specific user account for dynamic DNS registration credentials. We did that but the errors are not stopping.

Any suggestions? Any help would be appreciated.

share|improve this question
It sure would be nice if Windows told you something other than "Update Failed"... –  Jared Oberhaus Jul 13 '09 at 3:44

3 Answers 3

up vote 10 down vote accepted

SUGGESTION: You need to make sure that the reverse DNS is properly setup for the zone. I believe DNS auto-update populates both the forward (name to IP) and the reverse (IP to name) zones. If the reverse zone is not setup properly, the update could fail and give this errors. Bed reverse DNS can also trigger other strange behavior.

ALSO: It is not a problem to have DC, DNS and DHCP on the same server, unless the network is huge. However, you absolutely need to setup a second DC. Without a working DC, your network becomes a bunch of paperweights.

share|improve this answer
after setting up a reverse DNS, i see code 32 DNS Update Success in the audit log. Thanks! –  ssxuser Jul 1 '09 at 17:58
+1 for 2nd DC, nobody should have to learn that the hard way –  Kara Marfia Jul 1 '09 at 18:37

Note that a critical piece of getting this to work is that the DHCP and DNS server must be joined to Active Directory. I realize this isn't part of this specific issue, because it's mentioned that they are both joined to the domain, but it's still a requirement.

Please see my recent question...

share|improve this answer
Not really a factor here, since the DNS server is a DC. DCs must belong to their domain. –  duffbeer703 Jul 13 '09 at 3:56
Thanks, adjusted my answer. Just wanted to be sure that this prerequisite was covered for others running into problems like this. –  Jared Oberhaus Jul 13 '09 at 4:54

Have you tried unauthorizing and re-authorizing the DCHP server, now that you have different credentials?

share|improve this answer
no i haven't. would this be preferable to simply restarting the dhcp server service? –  ssxuser Jul 1 '09 at 16:12
I have unauthorized and then re-authorized the DHCP server. Unfortunately, I'm still seeing code 31 DNS Update Failed in the Audit log for DHCP. –  ssxuser Jul 1 '09 at 16:37

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.