Port
There are 2^16 ports (0 to 65,535).
0-1023 are reserved for system ports. Should NOT be used by user level processes.
Standard ports:
- 22: Secure Shell
- 53: DNS Lookup
- 80: HTTP
- 443: HTTPs
Special ports
Port '0' (Zero)
Tells the operating system to assign a random available ephemeral port.
Use cases: Tests
This is the best practice for tests when port is needed for running tests as it prevents port collisions between parallel test runs or other applications.
Use case: Flexible port
If your application does not require a stable port this is quite convinient to be able to stand up the app without experiencing issues due to clashes.