Ok, so on dev.domain.local, you don't have any other local zones on that DNS server correct? If you have other domain.local zones, such as a child, that would cause the issue you are experiencing.Guides and tutorials, visit ITGeared.com.

Hmmm, yeah. I think you've nailed it. I've finally got access to the DNS server itself and there are other zones which would tie up with what you've said. I've done a fair amount of my own reading on the problem wouldn't setting up DNS delegation in domain.local for ras.domain.local work?

I'm currently working on a new deployment of a Windows 2008 R2 Forest at work. The idea is in the long run to migrate all infrastructure in an existing Windows 2003 forest to the Windows 2008 forest. But for the time being the 2 forests will co-exist. See the enclosed diagram. What I need to set up is name resolution between a child W2k3 domain (dev.domain.local) and the new Window 2008 R2 domain. After doing a bit of reading, I thought the way forward would be setting up DNS conditional forwarders between the two domains. Each domain has it's own DNS server. I attempted this on friday and got "The server forwarders cannot be updated, A zone configuration problem occurred". As far as I know there aren't any firewalls between the domains, so can anyone shed some light on what I'm doing wrong and how to resolve this? Thanks in advance!!

I believe, based on your description, is that your issue is that you are going to have some trouble setting up a conditional forwarding on domain.local to the other two domains because the other domains are actually each a "child" of domain.local (from the DNS naming perspetive, not AD). On domain.local, you would have to set up "sudomains" and provide the NS records of the DNS servers in each subdomain. As far as conditional forwarding, are you indicating that you are unable to create a conditional forwarder on dev.domain.local pointing to ras.domain.local, and visa-verse?Guides and tutorials, visit ITGeared.com.

I'm unable to set up conditional forwarding from dev.domain.local to ras.domain.local. The idea is to set up a forwarder from ras.domain.local to dev.domain.local, but obviously I haven't got that far yet.

in domain.local, set up delegation for both ras and dev. As long as you do not replicate the domain.local zone (with the subdomain info) to ras or dev, you will be able to set up conditional forwarding on ras and dev. There are many ways to design DNS for name resolution, as you can see. Guides and tutorials, visit ITGeared.com.