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Why close ports in Windows?

Through open ports in the Windows operating system, you can become infected with a virus. In this article we will explain how and why to close ports in Windows.

November 15, 2018


    Close the doors! The call, so familiar to us, to close the door, after entering the room, is very relevant in setting up the computer's firewall. A huge number of computers on Windows OS are infected with the most dangerous viruses due to the fact that users irresponsibly approach to setting up the firewall. This is motivated primarily by the fact that they install antiviruses that protect them from all viruses.

    Unfortunately, installing an antivirus will not protect your computer from all possible threats. Most of the viruses that infect Windows OS penetrate through the open ports of the operating system. These ports are enabled by default in the operating system.

    Let us define the concept of “port”, imagine a queue of incoming connections to a computer from various programs with infected viruses. Each person in the queue is assigned a number in order to make it clear where to connect to the operating system. The operating system listens to the port, and if it sees a connection to it, it accepts it. Next thing technology. The virus enters the computer and begins to infect all that is possible. It can also open additional ports so that there are more connections to the computer from the outside and the infection is faster. To remain safe, you need to close the “doors”, that is, give the system a command not to listen to certain ports and reject all connections to them.

    The most vulnerable ports in Windows operating systems

    Examination of the largest computer infections made it clear that almost 90% of malicious traffic was sent through ports 135, 137, 139 and 445. These ports are used for:

        TCP port 445 - for file sharing
        TCP port 139 - for remote connection to computer
        UDP port 137 - to search for information on other computers
         TCP port 135 - to execute the command setting

    There are several ways to close ports in Windows. Let's look at them.

    Inexperienced computer users think that closing ports in Windows is very difficult and something can be broken. In fact, there is nothing difficult and at the same time closed ports will allow you to be protected from the threat of hacking into your computer and the loss of important data.

    The easiest way, which does not require installing additional software, is to use the Windows command line. They use the command line if any of the settings do not have a graphical interface, and you must tell the system to apply the settings manually.

    Before you run the command, you must open a command prompt. To do this, please do the following. Press the key combination Win + R, you will open the program "Run ...", in this program you need to type cmd and press the "OK" button or Enter on the keyboard. Then a black command window will open. Next thing is small, it remains to enter commands, just alternately copy them, paste into the command line and execute. The last digit in the command is the port number that you are closing with this command.

        add rule dir = in action = block protocol = tcp localport = 135 name = ”Block1_TCP-135 ″
        netsh advfirewall firewall add rule dir = in action = block protocol = tcp localport = 137 name = "Block1_TCP-137 ″
        add rule dir = in action = block protocol = tcp localport = 138 name = "Block1_TCP-138 ″
        add rule dir = in action = block protocol = tcp localport = 139 name = ”Block_TCP-139 ″
        add rule dir = in action = block protocol = tcp localport = 445 name = "Block_TCP-445 ″
        netsh advfirewall firewall add rule dir = in action = block protocol = tcp localport = 5000 name = "Block_TCP-5000 ″

    Using these commands, you can close the ports about which we wrote above, as well as a no less dangerous port that detects open services, and UDP port 138, which is responsible for NetBIOS.

    You can also close ports in Windows using third-party software. The principle of using such software is simple - they scan the system on open ports and offer to close the most vulnerable ports without entering commands. The most popular and easy-to-use software for closing ports in Windows is Windows Doors Cleaner. The principle of using the program is simple: after installation, run the program, and close the ports that it offers.

    Make a conclusion

    Closed ports do not give a 100% guarantee that your computer will be completely protected from viruses. The best defense is common sense. Install updates of the operating system, do not click on suspicious links on the Internet and do not install programs from unofficial sources. For more complete confidence that you are fully protected, you need to buy VPN. This will allow you to protect yourself from being intercepted by hackers.