In networking, a port is a communication endpoint. A port is normally tied to a specific process on your computer or server. It allows you to distinguise different kinds of traffic to a specific address. You can kind of see it like letters send to a specific person in a household: in networking different ports are for a specific application or service.

Ports allow for very efficient networking. You can have e-mail, webbrowsing and P2P networking all at the same time, because of ports. There are some common conventions for ports, such as for webbrowsing, file transfers and e-mail.

Some ports are reserved for common uses. They are part of the backbone of the internet and as a self-hoster, you should know about them:

Here you can find the default ports for some of the most used self hosted applications.