The DNS service provides name resolution service to other tasks within the app software, and can act as a relay for requests received from client machines.

Configuring the DNS service only requires the specification of one or more resolver DNS servers - resolvers are typically provided by your Internet Service Provider, and accept requests to resolve DNS names, performing the recursive process necessary to query all the necessary authoratative DNS servers.

The DNS service in the FB6000 is not itself a full recursive resolver - it merely sends the request to one of the listed resolver servers.