iX 6.0)

Appendix C 175

BIND 8.1 Enhanced Features

BIND 8 Highlights

Topology All other things being equal, when the server chooses a nameserver to

query from a list of nameservers, it prefers the one that is topologically

closest to itself. The topology statement takes an

address_match_list and interprets it in a special way. Each

top-level list element is assigned a distance. Non-negated elements get

a distance based on their position in the list, where the closer the match

is to the start of the list, the shorter the distance is between it and the

server. A negated match will be assigned the maximum distance from

the server. If there is no match, the address will get a distance which is

further than any non-negated list element, and closer than any negated

element. For example,

topology {

10/8;

!1.2.3/24;

{ 1.2/16; 3/8; };

};

will prefer servers on network 10 the most, followed by hosts on

network 1.2.0.0 (netmask 255.255.0.0) and network 3, with the

exception of hosts on network 1.2.3 (netmask 255.255.255.0), which

is preferred least of all.

The default topology is

topology { localhost; localnets; };

Converting From BIND 4.9.x

BIND 4.9.x conﬁguration ﬁles can be converted to the new format by

using src/bin/named/named-bootconf.pl, a perl script that is part

of the BIND 8.1 source kit.