19. Ports and Protocols

There are two types of ports: physical ports and logical ports.

Physical ports are the actual hardware connection points on devices like routers, switches, servers, and computers where network cables are plugged in.

Logical ports are numbered communication endpoints used by software and network services. They tell the system where data should go during a connection. A logical port is also called a socket.

Logical ports allow one IP address to handle many connections at the same time because different services can use different port numbers.

Some services are tied to common port numbers. For example, HTTP uses port 80 and HTTPS uses port 443 (can be altered to any port but mostly these are used).

Logical ports are grouped into three main ranges:

• Well-known ports (0–1023): used by common core services and protocols
• Registered ports (1024–49151): often used by vendor applications and specific services
• Dynamic / private ports (49152–65535): temporary ports used during active sessions and then released

When possible, systems should use the more secure version of a protocol.

Main Idea
Physical ports connect cables, while logical ports direct network traffic to the correct service or application.