Can you view your ip address?

Can you view what is on your ip address? If so, how do you do this? Also, what do you go to to set how long (if you can) it takes before your dynamic ip changes? I'm not sure if ipconfig has anything to with it, but mine wont open. It flashes a black screen and I can barely make out what it says when I make a quick screenshot of it. Oh, and also...on a forum, I just found out that many admins can view your ip addresses. Are they legally allowed to use it unless they're banning someone?