Linux networking beginner questions
I'm new to Linux but I'm messing around with my Ubuntu installations trying to figure out cool things that I can do with them. I'm running two virtual machines of Ubuntu on the same network. I'd like to be able to send commands from one machine to the other machine. There's a couple of things that I'd like to know how to do.
Firstly, how can I see what ports are open on one of the machines from the other one? I can open up a port on one machine, how can I see that that port is open from another machine? I know there are commands like telnet,netcat, that I've read about but they all seem to do a whole lot of things that I don't really understand.
Secondly, if I want to send a command from one machine to another, I assume I need to have a terminal/shell that connects to a terminal/shell on the other machine. If I want to send a command from A to B, and I open a port on B, can I link that port on B to a terminal/shell? How on machine A then do I talk to that shell?