The Netstat command will show you all of the connections that your computer is making to the Internet and to other devices on your local network. To run the Netstat command simply open your command terminal (on a Windows computer just type CMD into the search bar) then type "netstat" (without quotation marks) and hit enter. Give it time to run and you'll see all of the IP addresses to which your computer is connecting.
This new video from PowerCert explains the Netstat command and variants that you can add to the command to learn even more about what your computer is connecting to.
Applications for Education
The netstat command along with many other commands is one that my PC repair students and my Intro to Networking students learn early in the year as it is helpful in diagnosing problems.