We have a number of 2820's and are generally very pleased with them. Recently I noticed that when they were installed some of them were configured with the WAN1 DNS configured to our internal DNS servers but some were left at the default DNS servers provided by the ISP - I'm not talking about the Internal connection which does use our internal DNS servers but rather the 1st ADSL broadband connection (WAN1).

Is there any value to me changing them to all use our internal DNS servers or alternatively to all use the ISP provided values or even the OpenDNS servers that we use? Will using internal DNS have an impact on network performance?

For info: Each site has a DC that provides DHCP and DNS with the DNS forwarding to the OpenDNS servers

Thanks in advance!

This isn't really a DrayTek question, but a Windows server question. With Active Directory, your DC(s) should be the only DNS server(s) on your internal network. Your internal DNS will use the forwarders (OpenDNS in your case) as needed.

in addition that active directory indeed does not work with other DNS servers then the Windows built in:
The draytek DNS forwarder implementation is or was not very good in the past. Questions for AAA records were not ansewered, or, only A records could be resolved. So if you have a little more then a small network at home which mainly uses http and a little email, try to use something else then the router built in DNS server.

Thanks for the responses. Our internal DNS servers are indeed our DC's using OpenDNS as forwarders. All client PC's point to their local DC as the primary DNS server and one of the head office DC's as a secondary DNS server. As far as I can see the only time the Drayteks would be asked to resolve DNS would be when doing something like a ping diagnosis from the web interface at which point some of them will ask the ISP DNS servers whilst others will ask the internal DNS servers - I guess for the sake of consistency I'll change them all to look to our internal DNS servers, having thought about it a little more I really don't see it making a difference.

Thanks again