How to check if port is open on windows - Open Port

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How to check if port is open on windows

The knowledge of how to check for open ports is important especially when you own a windows device. Here is an article about how to check if port is open on the windows operation system.

This can be done using any of the available port checker tools online. There are freeware tools for Microsoft Windows which can be used to check if a port is open.

These free utilities are quite effective at scanning for open ports.

How to Check For Open Ports in Windows

When troubleshooting network connectivity issues, there are ways to check for open (or listening) ports. In this article, we will look at the port check tools available in order of their popularity.

1. NetStat.exe

The netstat.exe is a popular Windows command line located in the Windows ‘System32’ folder. It is very effective for checking for open ports or if a port is in use by a particular host.

The netstat command line to be used in checking for open ports in a local host should be entered in the command prompt (cmd.exe) as follows:

Netstat–an

This displays the results across four columns with protocol type, IP address, foreign address and the state as the headings respectively.

The column of significant interest is the content of the second column in the command prompt display.

The “o” parameter can be added to the netstat command to show the application process ID (PID). A process ID column appears in the result as a fifth column.

netstat –ano

 

Open Tasklist.exe to help identify the application using the open (listening) port from the command prompt.

2. TCPView.exe

The second on our list is TCPView.exe which is similar to the netstat.exe command. The difference between the two methods of checking for open ports is that TCPView.exe gives a detailed representation in a graphical format or graphical user interface (GUI).

By opting to use TCPView, you get to scan for which ports are open.

Also, as its extended benefit, it enables you to check both the local and remote TCP connection, the protocols that are being used as well as the processes involved.

TCPView can be downloaded from Microsoft SysInternals website and runs as a standalone application without any need to install.

3. PortQry.exe

An alternative method to check for open (listening) ports is the PortQry.exe Windows command.

It can be downloaded by visiting Microsoft Download’s Center and just like the TCPView command; it also runs as a standalone application.

The use of the PortQry.exe command line allows checking for open ports available on the local or remote host.

It works by downloading and extracting the executable file from the Download’s Center and opening a command prompt.

On the command prompt, enter portqry.exe and the parameter identifying the folder which contains the executable file.

It should be noted that the results obtained from running the portqry.exe are similar to that of the netstat.exe command except that it also shows the port statistics stating the number of port mappings and ports in each state.

How To Check If Port Is Open

It is very important to know the ports that are open on your computer because some ports are associated with special services and these ports have to be open for your computer to run properly. It is also important to check if port is open and which ports are open.

To check if port is open, you should enter “netstat-a” in the command line and it will return with a list of open ports.

Apart from the ports that are used for special services, all other ports should be closed because the more open ports you have on your system, the more vulnerable it will be to hacking.

This is because ports are the doors through which access to your computer can be gained.

Firewalls are the only locks that prevent access. Knowing the ports that are open is a step towards safeguarding your computer.

The special ports that should be open and their uses have been outlined below. All other ports should be closed or filter.

Here are the ports:

  • Port 7: This port is also referred to as Ping and Echo. It is used to retrieve the IP address of your computer and its gateway. This is done by typing ipconfig in the command prompt. It is also used for troubleshooting. This is done by typing ping and the number of your gateway. You will get a response after.
  • Port 21: This is known as the FTP. This is used to either upload or download files to or from a server when websites are being updated.
  • Port 25: This port is called SMTP. It works with applications like Thunderbird, Pegasus and the popular Microsoft Outlook to send emails. Gmail, Yahoomail and Hotmail do not need this port because they are webmail.
  • Port 53: This port is also known as DNS. This port helps to convert URL to the IP address of the website. Here is how it works. The computer does not understand the website you type on your web browser and you cannot cram the IP address of websites. So when you type the website, it is converted to the appropriate IP address for your computer through the process known as DNS. The computer now loads the page based on the IP address. Without DNS, you will have to be typing IP address and not the website. Imagine how difficult it will be.
  • Port 80: This port is known as HTTP. This is the route through which your computer gains access into the internet or to other websites. If this port is closed, you won’t be able to visit other websites.
  • Port 110: This port is called POP3 and it works with the same applications as Port 25 above to receive emails. It does not also work with webmail.
  • Ports 135 to 139: This is known as NetBios. This gives you the name of any computer on your network.
  • Port 443: This port is known as HTTPS, it does the same thing as Port 80 but for secure websites.

The above freeware utilities are the answer to the how to check for open ports question and they are useful in being able to troubleshoot network connectivity issues if the need arises and form a part of a network auditing toolkit or basic checks for vulnerabilities where necessary.


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