Using Untangle as backup DNS server

Hi Untangle Forums,

I am looking at the possibility of using Untangle as a backup DNS server for my network. Right now I have a Windows Server 2008 server serving as the primary DNS server for my network, if that server goes down then clients fail to reach the internet. I am aware that I can enter my ISP's DNS servers on the clients as the secondary DNS server but I figured that if I could configure Untangle to do this it would be a bit easier.

I also know that I can set up Untangle to point to my ISP's DNS servers and then point my clients to the Untangle server as the secondary DNS server. The setup that I am hoping to accomplish though is to have DNS entries replicated from my primary DNS server to my secondary DNS server (Untangle server), so that when I add a new client to the domain and the domain controller sees it the new DNS entry will get replicated to Untangle on the next replication cycle.

Is this scenario possible to accomplish and are there any tweaks that have to be done either on the primary DNS server or on Untangle to have this work properly?

Thanks in advance for any help you can provide.