Now that you have your name servers running, you might want to support more domains. What needs to be done? Nothing special, really. All you need to do is add more primary or secondary statements (version 4) or zone statements (version 8) to your configuration file. You can even add secondary lines to your primary master server, and primary lines to your slave server. (You may have already noticed that your slave server was primary master for 0.0.127.in-addr.arpa.)
At this point, it's useful to repeat something we said in an earlier chapter. Calling a given name server a primary master name server or a slave name server is a little silly. Name servers can be authoritative for more than one zone. A name server can be a primary master for one zone, and a slave for another. Most name servers, however, are either primary master for most of the zones they load or slave for most of the zones they load. So if we call a particular name server a primary master or a slave, we mean that it's the primary master or a slave for most of the zones it loads.