How To Check Open Ports In Windows

To know which port is open in window can be done easily. So you can check open port in windows by doing this. All you need is a program that displaces all TCP and UDP connections and their respective states.

And all windows computers have such program—Netstat. Even when you do not supply, it does it by default. The only exceptions are ports in listening mode (you can also use it to know the port that are in listening mode too)

Using Netstat on the server itself to check for open ports in windows

So, a program can open a port and there is no client connected to it. And Netstat can also help you figure out which port are in listening mode—like I have said earlier. How it does that? Simple.

Common port numbers are translated into the protocol usually associated with them by Netstat. For instance it converts IP addresses to their DNS names and also it translated port 25 to smtp.

You may want to see the port or IP address numbers. If you want to do that, you should use n-switch. The process identifier (PID) or even the executable will not be identified. It is Netstat default setting.

On the other hand, you can see the service within the executable that opened the port by using the b-switch. When you use it that is what it tells Netstat to do.

And there is the o-switch which you can use to show the same PID for a process. You should know that Task Manager does the same thing too.

Using Telnet from outside to check open ports in windows

You should know too that telnet is not a default option in window Vista or 7 and so it is not recognized as an external command or internal for that matter. It is also not recognized as an operable program or batch file too.

But here is what to do: Go to ‘Start’ on your windows, click it and go to’ Control Panel’. It will display options.
Click on ‘Programs’ (it is usually below in the option displayed). And you should locate ‘Turn Windows Features on or off’. Click it and wait for it to load. You will see this at the top; ‘’ To turn a feature on, select its box. To turn it off, clear its check box. A filled box means that only part of the feature is turned on’’.

In the displayed list below, scroll down and select ‘Telnet Client’. And then click ‘Ok’. That is it.

And that is how you check for open ports from within or from outside in windows. Pretty straight forward, right? It sure is.

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