DNS & BIND Cookbook

Chapter 11. IPv6

Introduction

IPv6 is tomorrow’s internetwork protocol -- perennially, it seems. BIND has supported IPv6 forward and reverse-mapping since Version 4.9.5, released way back in 1996. BIND 9, finally, added support for IPv6 as a transport, responding to queries received over IPv6.

The IETF -- the body that develops extensions to DNS, among other things -- briefly flirted with a very complex method of handling IPv6 forward and reverse-mapping, using A6 and DNAME records and “bitstring labels.” (Unfortunately, I wrote the fourth edition of DNS and BIND at just the wrong time and documented A6 and the rest.) Eventually, however, they opted to standardize on a system that uses AAAA and PTR records in a straightforward way, similar to the way A and PTR records work with IPv4 addresses.

Configuring a Name Server to Listen for Queries on an IPv6 Interface

Problem

You want a BIND 9 name server to listen for queries on an IPv6 interface.

Solution

Use the listen-on-v6 options substatement to instruct the name server to listen on any of the host’s IPv6 interfaces for queries. For example:

options {
    directory "/var/named";
    listen-on-v6 { any; };
};

Don’t specify the particular IPv6 address of one of the host’s interfaces: listen-on-v6 only supports any or none as an argument. The default, as of BIND 9.1.0, is none; that is, don’t listen for queries on any IPv6 interfaces.

Discussion

Before BIND 9.1.0, BIND 9 name servers listened on any of the host’s IPv6 interfaces by default. BIND ...