If you want a *detailed* explanation as to why, please ensure that you understand how the basic protocol works, first. There's no point in giving a technical explanation if you're unfamiliar with the background information.
Don't use CHAP. It's useless.
You can believe that, or you can spend days (weeks) reading about the protocol, the encryption methods, and the common use cases. After all that effort, you will conclude that CHAP is nearly useless.
Alan DeKok
OK. I believe you, and just accept that CHAP is useless. Since you have clarified that my dubious analysis of the protocols was indeed all wrong, can you at least point me to some good links on the web that explains the difference between these two protocols in the context of radius authentication. If you have time, that is. Best Tarkshya