What keys do you use with netstat commands and what do they mean?

• -a: Displays all active connections and listening ports. Includes TCP and UDP connections.
• -n: Shows addresses and port numbers in numeric form. Disables hostname and service name resolution, which speeds up output.
• -p: Displays the PID (process name or number) and the program name associated with the socket. Requires superuser privileges on most systems.
• -l: Shows only listening sockets.
• -t: Displays only TCP connections.
• -u: Displays only UDP connections.
• -s (--statistics): Shows protocol statistics (e.g., TCP, UDP, IP, ICMP).

Usage examples:

# Display all active TCP connections and listening ports in numeric form
netstat -ant

# Display all UDP listening ports with process information
sudo netstat -ulp

# Display TCP protocol statistics
netstat -s -t

# Example output of netstat -ant
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN
tcp        0      0 127.0.0.1:631           0.0.0.0:*               LISTEN
tcp        0      0 192.168.1.10:443        203.0.113.5:12345       ESTABLISHED