I am running Ubuntu Server and using putty to check on it from time to time. There shouldn't be any traffic at all on this machine unless I initiate it. About once/twice per month when I run 'vnstat -l' to check the traffic, I notice that it's transmitting and receiving more than usual.
I want to know exactly what it's doing. I have been a Windows admin for years and know my way around Microsoft like the back of my hand. I can look at the services/processes running on any Windows machine and easily identify them. I can't do this with linux yet. I want to be just as comfortable with Ubuntu (as I am with Windows), which is why I have set up this machine.
I would like to be pointed in the right direction here. I know a handful of basic commands and have some Linux cheatsheets with some vague suggestions, which usually suffice, but I am still not satisfied that my machine is safe.
I am running ufw with one open port, 22, for putty. When I use the machine for other things I usually open up other ports, such as 80, but immediately close it when finished.