I have a small network of computers which mostly access stuff online. I have a domain controller running on that network, which is also serving as the DHCP and DNS server.
I have configured DHCP (using the Scope Options) to provide the following IP addresses as the DNS servers for the network:
- 192.168.0.31 (my LAN DNS server, the primary DNS server)
- 18.104.22.168 (Google's DNS server, the secondary DNS server)
The DNS server addresses are being correctly handed out to the DHCP clients. However, I cannot resolve any LAN domain names using this pair of DNS servers, even using their FQDNs. If I remove Google's DNS server from the list, I can resolve LAN domain names but not anything online. It takes a little while (30 mins?) for the resolution of online domain names to stop working; presumably this is something to do with the DNS cache?
The same thing happens if I add Google's DNS server to the DHCP client manually, in addition to my LAN DNS server.
Obviously I've configured something incorrectly, or have missed a step (do I need to set up DNS forwarding, perhaps?). Any help you can provide will be gratefully received!