What's New in the Fourth version?

Besides updating the tutorial to cover the most recent versions of BIND, we've added a fair amount of new material to the fourth version:

More extensive coverage of dynamic update and NOTIFY, including signed dynamic updates and BIND 9's new update-policy mechanism, in "Advanced Features"
Incremental zone transfer, also in "Advanced Features"
Forward zones, which support conditional forwarding, in "Advanced Features"
IPv6 forward and reverse mapping using the new A6 and DNAME records, as well as bitstring labels, at the end of "Advanced Features"
Transaction signatures, also known as TSIG, a new mechanism for authenticating transactions, in "Security"
An expanded section on securing name servers, in "Security"
An expanded section on dealing with Internet firewalls, in "Security"
Coverage of the DNS Security Extensions, or DNSSEC, a new mechanism for digitally signing zone data, also in "Security"
A section on accommodating Windows clients, servers, and Domain Controllers with BIND, in "Miscellaneous"