Find Out What Process is Listening on a Specific TCP Port

There are two commands which are popular to get the result: netstat and lsof. We probably already have been familiar with

netstat -nlp

to list all the listening ports. We actually could do

lsof -Pnl +M -i4

to list all IPv4 ports or

lsof -Pnl +M -i6

to list all IPv6 ports as well.