How to view open network ports in Windows 11 and increase your security

Have you ever wondered what are the network ports that your computer with Windows 11 has openThe answer to this question is not only useful for the most curious, but can be fundamental if you want protect your system from external threats, better understand how your local network works, or troubleshoot connectivity issues. Know which ports are open can help you detect if any rogue program is doing its thing without your permission, or to ensure that a particular application can run smoothly.

Throughout this article I am going to tell you, in a pleasant and simple way, How to check open network ports in Windows 11, what tools you can use (both native and external), what the difference is between TCP and UDP protocols, and, above all, why it's crucial to master this aspect if you want to keep your computer secure and running smoothly. I'll also share tips and best practices to help you avoid confusion and be able to respond wisely to any situation related to your computer's ports.

What are ports in a network and what are they used for?

Before we get started, it's important to understand what ports are. In the field of computing and networking, a network port It is a number that serves to uniquely identify each service or application that communicates over a network (either local or over the Internet). Ports are associated with IP addresses and, together, allow data to reach the correct applicationFor example, port 80 is used for HTTP web traffic, and port 443 is used for secure HTTPS connections.

There are two main types of ports:

• Physical ports: These are the physical connections to your computer, such as Ethernet or USB, but in this article we are mainly interested in the logical ones.
• Logical ports: They are assigned by software to services and applications, and are the ones we will learn to control.

Understanding how these ports work is key to properly managing the security and connectivity of your equipment.

Why check for open ports in Windows 11

Checking which ports you have open isn't just a matter of curiosity. There are several compelling reasons to do so:

• Safety: Ports are points of entry and exit. Leaving a port open for no reason can be exploited by malicious software to enter your system.
• Problem resolution: If an application is not working or you have connection problems, it may be because the corresponding port is closed or locked.
• Services configuration: Online games, web servers or apps Video conferencing requires specific ports to be open in order to function properly.

Control open ports It gives you greater control over your network and helps you avoid unpleasant surprises.

Methods to view open ports in Windows 11

In Windows 11, you have several ways to see which ports are open or listening. Let's review the main ones, from the simplest ones, which don't require any installation, to some external (but secure and official) tools that give you an extra level of information.

1. Using Command Prompt or PowerShell

Windows 11 comes standard with several consoles commands that allow you to check open ports in real time. You can use either the Symbol of the system (CMD) , the PowerShell, which work the same in this case. It is important to open any of them with administrator permission to avoid access problems.

Step by step:

1. Open the Start menu and search for “Command Prompt” or “PowerShell.”
2. Right-click and select “Run as administrator.”
3. Once inside, type the command netstat -a and press Enter. You can also use netstat -an o netstat -ab if you want more detailed information.
4. In the list that appears, look at the "Local Address" column: the number after the colon is the open portThose with the "Listening" status are the ones actually in use at the moment.

Points to consider:

• This method requires no installation and is fast, but it is not always easy to associate each port with its specific application.
• In the "Remote Address" column, you can find clues about the name of the app using each port, although it's not always obvious.
• The command netstat -ab It directly shows you the name of the process associated with each port, but it may take a little longer.

2. Windows Resource Monitor

If you're looking for a more visual and detailed method without leaving Windows tools, try Resource Monitor.

How to access:

1. Go to the start menu and search for “resource monitor.”
2. In the window that opens, go to the “Network” tab.
3. Under "Network," click "Listening Ports." Here you'll see the complete list of ports and the applications using them, both for TCP and UDP.

Advantages: Allows see at a glance which processes use each port, making it easier to detect suspicious or unnecessary connections.

3. Third-party tools for port scanning

If you want to go a step further and access advanced information, I recommend some external applications widely recognized for their effectiveness and security.

• CurrPorts: A free, portable tool that shows you all open ports, the associated process name, protocol, local and remote IP address, and connection status. You can download it from the official website and it doesn't require installation. It allows you to export reports and view detailed properties for each process.
• TCPView: Similar to CurrPorts, it's a simple, visual utility developed by Sysinternals (Microsoft). It offers real-time information about processes and ports, allows you to close suspicious connections, and view the status of each port.
• PortQry: It's an advanced utility for users who need to analyze both local and remote ports. It allows you to check the status of specific ports by running commands from the console and provides comprehensive information on the usage and status of each TCP or UDP port.

Important Note: Always download these tools from their official websites to avoid risks of malware.

4. Online tools for port scanning

There are also web services to check open ports, especially useful if you want to see which ports you have accessible "outwards", that is, to confirm that your router or firewalls leave no holes unprotected.

• WhatsMyIP: Its "Port Scanners" section allows you to scan specific ranges of ports or common services (DNS, FTP, SSH, game ports, etc.). It is easy to use and does not require installation, although you obviously need an Internet connection to access it.
• HideMy.name: A web-based tool that uses the nmap command to scan ports. You can choose "Use my IP address" and select the most common ports or enter a specific range. It also allows you to check a domain's ports simply by typing the corresponding URL.

These websites are useful for seeing which ports you have accessible "outward," that is, to confirm that your router or firewall doesn't leave any holes unprotected.

How are ports used? TCP and UDP protocols

Network ports in Windows do not work in any way, but are supported by two major transport layer communication protocols: TCP and UDPEach one responds to different needs and offers advantages and disadvantages.

What is the difference between TCP and UDP?

• TCP (Transmission Control Protocol): It is the most reliable protocol, as it establishes a prior connection, checks that the data arrives intact, and, in case of error, requests retransmission. It is ideal for tasks where the reliability is key: file transfers, web browsing, emails, etc. However, it is somewhat slower due to these security and control mechanisms.
• User Datagram Protocol (UDP): It doesn't guarantee data delivery or integrity; it uses a "fire and forget" method, which is much faster and lighter. It's perfect for real-time streaming, such as video games online or streaming, where speed matters more than absolute reliability.

The choice between TCP and UDP It will always depend on the type of application and your needs. If you're looking for reliability, use TCP; if you prefer speed and tolerate occasional data loss, stick with UDP.

Types of ports and how to identify them

Not all ports are used in the same way or pose the same level of risk. You may encounter:

• Well known ports: They are those that go from 0 to 1023. They are assigned to standard services such as HTTP (80), HTTPS (443), FTP (21), etc.
• Registered ports: They range from 1024 to 49151. They are usually assigned by specific applications as needed (email clients, online games, etc.).
• Dynamic or private ports: From 49152 to 65535. They are assigned dynamically and are usually open temporarily when an application needs them.

Recognizing each of these types is essential, as some services require specific ports to function, while others only open ports temporarily. If you're unsure about whether to close one or the other, consult the application's documentation or seek advice before making a decision that could affect its operation.

Risks and dangers of open ports

Leaving ports open out of ignorance is usually not a good idea. Although some are essential for certain applications to work, the more ports are accessible, greater chances of attacks there are.

Main risks:

• Malware and unauthorized access: An open port can be exploited by malware or Trojans to enter your computer and perform malicious tasks.
• Vulnerabilities: Attackers use automated tools to detect open ports and exploit potential security flaws.
• DDoS attacks: The more ports you have open, the more vulnerable you are to denial of service attacks.

Therefore, it is essential to reduce open ports to only those necessary., properly configuring your firewall and keeping your system updated with the latest security patches. For more details, see how to block or force detection of USB ports in Windows.

How to close unnecessary ports in Windows 11

Once you've identified the ports you don't need, you can easily close them using the Windows Firewall:

1. Open Windows Firewall with Advanced Security.
2. To block incoming connections: Click "Inbound Rules" > "New Rule" > "Port." Select TCP or UDP and specify the port you want to block.
3. For outbound connections, the process is similar, but in “Outbound Rules.”

Also, if you use a router, access its settings (by entering the IP address in your browser) and adjust the rules to close any unnecessary ports, after correctly identifying them.

Verify that the changes are effective by rescanning with netstat, CurrPorts, or online tools.

When is it necessary to open a port?

Although the general trend is to keep all non-essential ports closed, there are cases in which opening ports is advisable:

• Online games: Many need specific ports to connect to other players.
• File sharing: For communication between devices on the same network.
• Web servers: When you host your own site on your network, you must open port 80 (HTTP) or 443 (HTTPS).
• Video calls: Some platforms use specific ports to ensure call quality.

Learn about the ports each application requires and avoid opening more than necessary. Keep everything up to date to reduce risks.

How to know which process uses each port?

When scanning your ports, you may see one you don't recognize. To identify which process opened it, use commands like netstat -ab in CMD or tools like TCPView or CurrPorts, which show the process and its path on your computer. If you detect unknown processes, investigate before closing them; they could be system services or potentially dangerous programs that should be removed.

What happens if you have all the ports open?

Although It is possible to have all ports open, actually represents a very high risk. The more ports are accessible, more doors open for attackers or malwareYou should only keep open the ones you really need and protect them with firewalls and strict rules.