Either one of the following commands could show you the process which is running a specific port
- lsof -i :<port>
- netstat -tulpn | grep :<port>
Here is an example on my Ubuntu server.
root@li266-91:~# netstat -tulpn | grep :80 tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 31024/apache2
Apache is running on port 80.