Ports are numbers that identify the entry and exit points of your computer. Computers divide one physical port connection into thousands of virtual port connections, most of which are never used. All communications protocols have designated entrance ports to your computer. For example, traffic sent using HTTP for Web pages generally travels through port 80. Your computer’s ports are either open or closed. An open port allows any information to flow through it and can make your computer vulnerable to hackers. A closed port blocks incoming traffic.