Suppose you have a BIND-9 server on an intranet acting as master or slave for the root (‘.’) zone. Then, for an extranet connection you put a forward zone in named.conf….Voila, named will not forward any requests no matter what you do if it is slave (or master) for root.
How do you solve it ? Well, you have to put a ‘dummy’ delegation in the root zone file for the zone then named will override this with your forwarders directive.
Simple when you know how….