what are port scans and ow do I close a port ? for seurity reasons I wanted to know whats a port scan some of the information thats here is a little vague, but I did get a lot of information also wanted to kow how di I know a port is running and how do I close it or black it off ????

Hello and thank you everyone for your help in helping me configure my computers on a P2P in my home. I hope that I am posting this in the right place.

thank you all