I'm interested to know more about how certain network protocols work (like SSH or FTP for example). Is there a program that can facilitate connecting to computers on the network and communicating with them? I'd prefer a GUI program, and I'd prefer for it to work on OS X.
For example, I use a program that allows me to test REST services. I can use it to send requests in the HTTP method of my choice, and analyze the response.
Of course, this program is made for HTTP requests. I'm looking for a much more general way to look at protocols.