2. Setting up a sub-domain

A sub-domain is a way to hand off authority to another administration. Setting a sub-domain involves mostly telling where the DNS which manages this sub-domain is located. This is a two step process. First, you must define which machines are managing the sub-domain. Next, you must give the IP numbers of those machines, if they are part of the sub-domain. A DNS of a domain need not be part of the domain it is managing.

2.1 An example: Setting the sub-domain sub.foo.com

Some facts first...

• This machine is the DNS of foo.com.
• You want to create the sub-domain sub.foo.com.
• The primary DNS of the sub-domain will be dns.sub.foo.com.
• The secondary DNS of the sub-domain will be ftp.sub.foo.com.

Perform these steps...

• Edit the record sub.foo.com (it will be a new file).
• Under the section DNS advertising enter dns.sub.foo.com and ftp.sub.foo.com.
• Edit the record dns.sub.foo.com and set the IP number(s) of this machine.
• Repeat the operation for ftp.sub.foo.com.

Now your DNS knows two things: Which machine(s) is(are) responsible for the sub-domain sub.foo.com, and, how to reach it. This information combination is often referred to as the glue record.

2.2 Not setting a sub-domain

It is not necessary to setup a complete sub-domain just to have a sub-category of machine. Suppose that for a project, you want to refer to two machines as ftp.project.foo.com and www.project.foo.com. You can simply define these machines' IPs using the host information screen. The information will be dispatched in the foo.com database.