Network Administrator may use a private DNS server to resolve internal hostnames; however, forwarding all the DNS queries to that private DNS server might be inefficient. In such cases, we may use Conditional DNS Forwarding so that only the specified domains will be sent to and resolved by the private DNS server.
To setup Conditional DNS Forwarding, go to Applications >> LAN DNS / DNS Forwarding, and click on an Index number to add/edit a profile:
To verify this function, we use the LAN Port Mirror to copy the WAN traffic. From the captured packets, we can see when a LAN client sends DNS query for “www.example.com” to a public DNS server, the request will be forwarded to the DNS server at IP “100.100.100.100”.