Can't add a computer to domain

[dawks]

Ok, for the last 5 years, our AD domain has been working fine. I could add/remove computers at any time, up to last week. I had a Vista laptop that was in transition to a new user, but in the mean time someone was going to take it offsite, so after cleaning it up, I removed it from the domain.

Fast forward to this week, and I'm trying to add the computer back to the domain, but I am getting an error message.. "AD DC for the domain xxx could not be contacted". In the details it says "DNS name does not exist".

I've tried nslookup and it says "Non-existent domain"

Nothing has been changed on the DNS server or the AD DC by myself. All the DNS records appear to be there.

Any suggestions?

SOLVED : Firewall was on.. never came across that before. Be sure to turn the local Windows firewall off when attempting to add a computer to a domain.

 

[RebateMonger]

Check the NIC's network propertes and compare those to another PC on your Domain.

 

[Genx87]

If you ping the domain name does the ip come back of your domain controller?

 

[dawks]

Check the NIC's network propertes and compare those to another PC on your Domain.

The properties of the NIC are similar, I verified this before posting. I even flushed DNS cache and rebooted (several times).

So the one strange thing is, we have a direct connection to another organization, and I guess they started running an IPv6 DHCP server in the last few days and failed to mention it. The thing that confused me is, this Vista laptop received an IPv4 address from our server, and an IPv6 address from their server. The strange thing, their DHCP server over-rode our DHCP servers IPv4 DNS server entries. So the laptop was using their DNS servers initially even though our v4 DHCP server was providing them.

After that I disabled IPv6 (took a couple tries since I had to do it on both WiFi and wired - just disabled WiFi for now). Then I ipconfig/released, then /flushdns, then reboot, then /flushdns once more. The Vista system now has the proper DHCP info and DNS entries, but still cannot contact the DC. I tried un-joining/rebooting/joining an XP box to the domain and its working fine.

So its this Vista box thats stuck now. Even with proper DNS and a cache flush, I'm still getting the same problem.