Port
A port is just a number that the host associates to an application. Ports break down into 3 groups
- 0-1023 are well known ports,
- 1024-49151 are user or registered ports, and
- 49152-65535 are ephemeral ports.
Well known ports are used for system processes and protocols. For example port 80 is used by webservers for HTTP.
Registered ports are used for user applications that need a port to work off of.
The ephemeral ports or dynamic ports are used for private or temporary uses for example to connect to a web browser and receive a web page.