Ports
In computer networking, a port or port number is a number assigned to uniquely identify a connection endpoint and to direct data to a specific service
Port numbers are connected to an IP address and often use either TCP or UDP transfer protocols. Thats why you have TCP/IP for internet!
There are 65,535 TCP ports available
- Port numbers are 16-bit unsigned integers
- 0–1023 are well-known ports
- used by system-level things like HTTP, HTTPS, SSH
- 1024–49151 are registered ports
- often used by apps like MkDocs, Django, etc
- 49152–65535 are ephemeral/dynamic ports
- used temporarily by apps for short-term connections
Check Ports Used
On MAC:
lsof -i -P -n | grep LISTEN