As many have noted, plain handling of '/etc/*' files will be no use with MacOSX, as it uses NetInfo. BTW, as far as I know, NetInfo can be configured to run with LDAP, ActiveDirectory (gasp) and NIS.
I might not have understood the question, are you planning to setup a DNS server or to setup the DNS information of a MacOSX machine? As stated, setting up a DNS server is no plain task, and I would recommend having a great great deal of patience.
Moreover, there are several MacOSX specific books out there, just do a quick search on amazon.com.
dani++