Once you register a domain name, you can create subdomains within it as long as you set up a DNS server on your network to keep track of the subdomain names and IP addresses.
For example, if you register the domain name “example.com,” you could create subdomains such as “host1.example.com,”“mail.example.com,” or “www.example.com.” A server in a subdomain could be named “primary.www.example.com,” or “backup.www.example.com.” The DNS server for example.com keeps track of information for its subdomains, such as host (or computer) names, static IP addresses, aliases, and mail exchangers. If your ISP handles your DNS service, you’ll need to inform them of any changes you make to your namespace, including adding subdomains.
The range of IP addresses for use with a given domain must be clearly defined before setup. These addresses are used exclusively for one specific domain (never by another domain or subdomain). The range of addresses should be coordinated with your network administrator or ISP.
Step 2: Learn and plan
If you’re new to working with DNS, learn and understand DNS concepts, tools, and features of Mac OS X Server and BIND. See “Where to Find More Information” on page 41.
Then plan your Domain Name System Service. You may consider the following questions when planning:
•Do you even need a local DNS server? Does your ISP provide DNS service? Could you use Rendezvous names instead?
•How many servers will you need for anticipated load? How many servers will you need for backup purposes? For example, you should designate a second or even third computer for backup DNS service.
•What is your security strategy to deal with unauthorized use?
•How often should you schedule periodic inspections or tests of the DNS records to verify data integrity?
•How many services or devices (like an intranet website or a network printer) are there that will need a name?
•What method should you use to configure DNS?
There are two ways to configure DNS service on Mac OS X Server. First, and recommended, you can use Server Admin to set up DNS service. For more information, see “Managing DNS Service” on page 21 for instructions.
The second way to configure DNS is by editing the BIND configuration file. BIND is the set of programs used by Mac OS X Server that implements DNS. One of those programs is the name daemon, or named. To set up and configure BIND, you need to modify the configuration file and the zone file.
Chapter 2 DNS Service
19
