BIND version 9 is a major rewrite of nearly all aspects of the underlying
BIND architecture.  Some of the important features of BIND 9 are:

DNS Security
     DNSSEC (signed zones)
     TSIG (signed DNS requests)
IP version 6
     Answers DNS queries on IPv6 sockets
     IPv6 resource records (A6, DNAME, etc.)
     Bitstring Labels
     Experimental IPv6 Resolver Library
DNS Protocol Enhancements
     IXFR, DDNS, Notify, EDNS0
     Improved standards conformance
Views
     One server process can provide multiple "views" of
          the DNS namespace, e.g. an "inside" view to certain
          clients, and an "outside" view to others.
Multiprocessor Support
Improved Portability Architecture

WWW: http://www.isc.org/products/BIND/bind9.html