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

There are 65,535 TCP ports available

• 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

Citations

wiki - https://www.wikiwand.com/en/articles/Port_(computer_networking)