Steve Fenton

Find out what is running on a particular port

Ever wondered what is tying up one of your ports when you try to spin something up and get the “already a process listening on port 182” error message?

Well enter netstat, which is handy utility for finding out what ports are taken.

The basic command is:

netstat

This will crawl your ports and give you a list of ports that are taken.

Proto  Local Address          Foreign Address        State
  TCP    127.0.0.1:1282         MACHINE:1283       ESTABLISHED
  TCP    127.0.0.1:1283         MACHINE:1282       ESTABLISHED

This isn’t enough, so you’ll probably want details of the app that is causing the port to be taken. So you can use:

netstat -b

If you get the message “The requested operation requires elevation”, either hold your computer above your head, or run command prompt in Administrator mode.

Proto  Local Address          Foreign Address        State
  TCP    127.0.0.1:1282         MACHINE:1283       ESTABLISHED
 [firefox.exe]
  TCP    127.0.0.1:1283         MACHINE:1282       ESTABLISHED
 [firefox.exe]