Analogy
- Think of your server as a large building.
- Ports are doors of that building
- firewall decide which person(application or process) can access which door(port)
- to keep this standardize many applications has standard-ports
Important
- Each port is unique on a device
- So you can’t have two applications listening on the same port
- if you try to use a second application on the same port you will get an error saying “port already in use”
ss - socket statistics
only thing we are going to use is service for RHCSA
