Using netstat to see the listening processes

To see if a program or process is listening on a port, ready to accept a packet, use the netstat program.

netstat -tulnp

The arguments to the netstat program are listed below:

•t – Show TCP

•u – Show UDP

•l – Show only listening processes (netstat can show both listening and all established connections, i.e. as a client too)

•n – Do not resolve network IP address names or port numbers

•p – Show the process name that is listening on the port