DNS & BIND Cookbook

Chapter 6. Delegation and Registration

Introduction

As the administrator of one or more zones, you need to manage two kinds of delegation: from your zones’ parent zones to your zone, and from your zones to their subdomains. Both are ongoing processes:

• After registering a domain name (as in Section 1.6), you still must update the delegation any time the set of authoritative name servers changes. Recipes Section 6.7 and Section 6.8 describe ways of handling this as painlessly as possible.

• After delegating a subdomain of your zone to a set of name servers, you must check the delegation periodically (Section 6.6) to make sure the delegation remains correct.

You also need to manage this delegation for two kinds of zones: forward- and reverse-mapping zones. Delegating reverse-mapping subdomains that correspond to a network or subnet involves more than you might expect. It’s covered in Recipes Section 6.4 and Section 6.5.

Delegating a Subdomain

Problem

You want to delegate a subdomain of your zone to a set of name servers.

Solution

Add NS records to your zone’s data file delegating the subdomain to the name servers. For example, to delegate the baz.bar.example subdomain to the name servers ns1.baz.bar.example and ns2.foo.example, you’d add these two NS records to the bar.example zone data file:

baz.bar.example.    IN    NS    ns1.baz.bar.example.
baz.bar.example.    IN    NS    ns2.foo.example.

In this example, you’ll also need to add an A record for ns1.baz.bar.example, even though the name server’s A record ...