First of all, there is no such thing as iPlanet web Server Enterprise Edition 6.5. The latest version was 6.0, and there is no 6.5 planned. I'm guessing, based on your quotes from the documentation, that you are talking about iPlanet Application Server, and not iPlanet Web Server.
You will have to get a fixed IP address from your network administrator. You will also need to know a domain name that will resolve your hostname. If you don't know this, your network adminstrator will be able to help you with this as well.
Once you have these two things you can configure your box with the information. It is pretty well documentated in the install guide. (
http://docs.sun.com/source/816-5788-10/prep.htm#46802 ). But, in short, open up Settings>Control Panel>System>Network Identification>Properties to enter the domain name. Under the TCP/IP settings
you should be able to specify the IP address.
David