You will need a computer with the following software installed.

1. A Web Server--You can run Perl and CGI on just about any computer (Mac, Windows, or Unix), but it's best if you do the exercises on a computer running the same OS as what you will use for your production work. It's also better if you can experiment on a machine that you can crash now and then without upsetting the apple cart. Try loading Linux and Apache on an old spare 486 for a nice, fast local Unix environment.
2. Perl--Version 5.003 or later. This needs to be installed on the same system as your Web server.
3. A Web Browser--It doesn't need to be installed on the same computer, but it does need to be able to access the server via a network connection.
4. TCP/IP: Whatever operating system you are using on your server needs to have TCP/IP installed. If it's a Unix system (e.g. Linux, BSD, Solaris, etc.) then it probably already has TCP/IP installed. If it's Windows or MacOS you may need to do something to install it.