Q: How do use DNS from inside a firewall? A: A couple of hints: `forwarders', `slave', and have a look in the literature list at the end of this HOWTO.
Q: How do I make DNS rotate through the available addresses for a service, say www.busy.site to obtain a load balancing effect, or similar? A: Make several A records for www.busy.site and bind 4.9.3 or later will round-robin the answers. It will not work with earlier versions of bind.