You can detect which process is bound to what port number by using lsof command. Simply specify the port number you are interested in with "-i:<port-number>" option.
For example, to find out which processes are using port number 631, run the following command.
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME cupsd 776 root 10u IPv6 9353 0t0 TCP [::1]:631 (LISTEN) cupsd 776 root 11u IPv4 9354 0t0 TCP 127.0.0.1:631 (LISTEN) cups-brow 953 root 8u IPv4 9930 0t0 UDP *:631
In the above, "-n" option prevents automatic conversion of host IP address to host name, and "-P" option prohibits conversion of port number to port name. In this example, cupsd and cups-brow processes are using TCP and UDP port number 631, respectively.
To see a list of all open TCP ports, along with their associated programs/processes, you can run the command below.
Subscribe to Ask Xmodulo
Do you want to receive Linux related questions & answers published at Ask Xmodulo? Enter your email address below, and we will deliver our Linux Q&A straight to your email box, for free. Delivery powered by Google Feedburner.
Did you find this tutorial helpful? Then please be generous and support Xmodulo!