Using a Cisco router as DNS proxy

This configures the router to forward DNS requests to other servers on behalf of the client. It is useful on smaller networks without a dedicated DNS server, simplifying administration by allowing you to point DNS on the clients to the router. I’ve also used it on a network with an unstable server that required frequent reboots which took 30 minutes. Adding the router as the secondary DNS in DHCP allowed the clients to still have usable internet access while the server was out of action.

(config)# ip name-server x.x.x.x
(config)# ip dns server