Another way to help discover how SSH works is to compile your own openssh server, instrumenting it with your own printfs, and see exactly what it's doing. I did

Another way to help discover how SSH works is to compile your own openssh server, instrumenting it with your own printfs, and see exactly what it's doing. I did this at one point, and it helped immensely to write a (horrifyingly insecure) homegrown SSH client. It was at least a good learning experience.