That's a great question! While you can run netstat without sudo to see the network connections, the -p (process) option is exactly why sudo becomes necessary.
Here is why:
1. Security and Privacy
In Linux, information about which process owns which network socket is considered sensitive. If any user could see every process running on the system and what they are doing on the network, it would be a security risk.
2. Process Ownership
- Your own processes: Without
sudo,netstatcan only "see" processes that belong to your current user (labex). - System/Root processes: Many network services, like
sshd(SSH),nginx, orsystemd-resolve, run with root (administrative) privileges. - The Result: If you run the command without
sudo, you will see a-in the PID/Program name column for any service owned by root or another user, and you will likely see a warning at the top of the output: "(Not all processes could be identified, non-owned process info will not be shown...)"
Summary
- Without
sudo: You see that a port is open, but you don't know who (which program) is using it if it belongs to the system or another user. - With
sudo: You gain the privilege to look into the system's process table and "map" Every single open port to its specific Process ID (PID) and Program Name.
In cybersecurity and system administration, knowing the "who" is just as important as knowing the "what"!
