Lesson 3

Implementing a DNS Name Resolution Strategy

4-33

Creating Zones

A zone is an administrative entity you create on a DNS server to represent a discrete

portion of the namespace. Administrators typically divide the DNS namespace into

zones to store them on different servers and to delegate their administration to different

people. Zones always consist of entire domains or subdomains. You can create a zone

that contains multiple domains, as long as those domains are contiguous in the DNS

namespace. For example, you can create a zone containing a parent domain and its

child, because they are directly connected, but you cannot create a zone containing

two child domains without their common parent, because the two children are not

directly connected (see Figure 4-7).

adatum.com

hr.adatum.com

sales.adatum.com

Valid zone

adatum.com

hr.adatum.com

sales.adatum.com

Invalid zone

F04pm07

Figure 4-7

Valid zones must consist of contiguous domains

You can divide the DNS namespace into multiple zones and host them on a single DNS

server if you want to, although there is usually no persuasive reason to do so. The DNS

server in Windows Server 2003 can support as many as 200,000 zones on a single

server, although it is hard to imagine what scenario would require this many. In most

cases, an administrator creates multiple zones on a server and then delegates most of

them to other servers, which then become responsible for hosting them.

Understanding Zone Types

Every zone consists of a zone database, which contains the resource records for the

domains in that zone. The DNS server in Windows Server 2003 supports three zone