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 (AAAA)
     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, including working threads in this version

BIND 9.5 has a number of new features over previous versions, including:
GSS-TSIG support (RFC 3645), DHCID support
Experimental http server and statistics support for named via xml
More detailed statistics counters, compatible with the ones supported in BIND 8
Faster ACL processing
Efficient LRU cache cleaning mechanism.
NSID support (RFC 5001). 

WWW: http://www.isc.org/index.pl?/sw/bind/index.php

- Doug Barton
DougB@FreeBSD.org