Port Reference Cheat Sheet

What network ports are

A port is a number that identifies a specific process or service on a device, allowing multiple network services to run on the same IP address without conflicting. Ports 0-1023 are "well-known ports," reserved for common, standardized services.

This reference table lists the most commonly used ports and what they're typically used for — useful for firewall configuration, understanding network traffic, or general troubleshooting.

A note on port scanning

Actively scanning ports on a remote server requires direct network access and specialized tools — it isn't something a browser can safely or legally do automatically. This page is a reference cheat sheet rather than a live scanner, useful for looking up what a port number typically means when you encounter it elsewhere.