How to Identify Open Ports on local computer

[RasMus]

Is there any way to identify or list all the ports that are free as well as already in used by different applications on a PC? This is because Network security is a critical issue for businesses because of the potential for data theft, denial-of-service (DoS) attacks, and other threats, and if such things possibilities are there then it will be needed to search the solution on it, Please help...

[Janhavi4U]

To identify ports, open a command console and type the following command:

netstat -a

and this same command Have you may tried using unix "netstat" command? I think the "-a" option gives all ports which then you can filter further with a grep pipe. For example:

% netstat -a |grep abc

And To view an IP address for local and remote addresses rather than host names, add the -n switch:

nestat -an

[KaramChand]

One thing to try there is opening up the task manager? The easiest way to identify and begin monitoring a network port is to look in the services file included with every modern TCP/IP stack. That's C:\WINDOWS\SYSTEM32\DRIVERS\ETC\SERVICES under Windows (Hint: You can use Notepad to view or edit the file -- just double-click on it and choose notepad from the list), or /etc/services under most Unix variants.processes and look for the rnaapp. If you find that there highlight it and click the end task button. Otherwise you would need to find a 3rd party program that lists all active processes similar to what is already seen there.

[Otto]

There are also numerous freeware utilities for windows that will show you used ports. I use software to connect to and program alarm systems and various cctv units. On occasion we (other techs and I) get errors like that. Typically we end up figuring out which rogue app is using the port and shut it down, but an app that would list all the ports being used would save us valuable time.