The communication between remote computers connected in your LAN or within Internet realized by this ports. Each port have a number and most important ports have names. Think for this ports like small doors. Through this doors any software program perform communication over TCP/IP networks.
Each computer connected to some TCP/IP network have several opened ports. But more client PCs will not set and they have many opened ports, which are not using and only can open some hackers doors for the security. To close ports, go to Start > Settings > Control Panel > Network Connections > Your_Network_Connection_Name > Properties.



