In this text, we use Ethereal, an open source network protocol analyzer, to examine traces of real network activity. Ethereal is free software released under the GNU General Public License. You are free to install Ethereal on as many computers as you like without paying any license fee. You can get more information about Ethereal from
http://www.ethereal.com.
Once Ethereal is installed, navigate to "home.html" on the CD. Choose a trace file to open from the Chapter Menu of Trace exercises.
You may want to consider associating the Ethereal executable with all files ending in .cap so that Ethereal starts automatically when you click on a trace file in your browser. In many systems, you can do this by right clicking on a trace file and choosing Open With. When you choose to open a file with Ethereal, choose to always open files of this type with the same executable.
