Quiz: ports and firewall

Several correct answers

A service will not start: Address already in use on 0.0.0.0:8080. Which commands help find who holds the port and stop it properly?

• A ss -ltn without sudo
• B systemctl status PID with the number from the ss output
• C sudo kill -9 PID as the first step
• D sudo ss -ltnp 'sport = :8080'