DNS configuration options
Master DNS (Maintains its own Zone files)
Slave DNS (Copies Zone files from the master)
Caching DNS (Doesn't have Zone files; caches lookups)
Unix DNS software
BIND (Berkeley Internet Name Domain) v4.x, v8.x, v9.x
djbdns (D.J. Bernstein's DNS )
pdnsd (Proxy DNS daemon)
dnscache (Proxy DNS server)