List all ports:
netstat -a
List all listening ports:
netstat -l
List listening TCP ports:
netstat -t
Display PID and program names:
netstat -p
List information continuously:
netstat -c
List routes and do not resolve IP to hostname:
netstat -rn
List listening TCP and UDP ports (+ user and process if you're root):
netstat -lepunt
Print the routing table:
netstat -nr