DNS Forwarding iRule on F5 GTM Listener

To do this with an iRule, use the "pool" command to select the pool of nameservers you want to forward the query to. The query will bypass on-box BIND, and be proxied instead. This will need to be an LTM iRule attached to the Virtual Server, not a GTM iRule attached to a Wide IP.

Another way to do this, without an iRule, is to define the zones in ZoneRunner as "forward" type zones, and let BIND do the forwarding for you.