Sometimes you need to know what application is using a specific port. Here is the syntax so I can remember how to do it:
sudo netstat -lpn |grep :{PORTNUMBER}
Just replace {PORTNUMBER} with the port in question:
sudo netstat -lpn |grep :3306
When you do that you’ll get an output sort of like this:
tcp 0 0 198.183.217.196:3306 0.0.0.0:* LISTEN 880/mysqld