Lsof port command

From KallestadWiki

You may be familiar with the following command:

netstat -lt

which basically spells out the listening port activity on your server. Sometimes you see something there (or with another netstat command) that doesn't look right.

The following lsof syntax will tell you which programs are listening on a given port:

lsof -i :port

This requires lsof to be installed, which isn't necessarily there. Here's a good getting started document, and here's the link to the project page at fresh meat.