Ports

Take a look at your system. Is it running 50 different processes you know nothing about? If we take some random Windows XP install and run netstat -aon inside a CMD window, what might we see?

When your web browser or email program connects to another computer on the Internet, it does so through a TCP/IP port. If you have a web server or FTP server running on your computer, it opens a port to which other computers can connect. Port numbers are used to distinguish one network service from another.