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How to find your port number

Jun 19, 2019 · 3 min read

How to find your port number

You might sometimes need to open a port to make applications work properly. You’ll need to know its number to do that, but how are you supposed to find it? It’s not as complicated as it might sound. Read on to find out how.

A port is like a gateway to the internet. Every device connecting to the internet uses them so that different applications could establish connections simultaneously. If you browse the web, download files and use a printer at the same time, all these operations use different ports. For example, File Transfer Protocol (FTP) data transfers use port number 20 while HTTPS uses 443.

What is my port number?

While an IP address is attached to a device, port numbers are attributed to different processes and connections within that device. They are used to make these processes identifiable on the internet and help the receiving end on the web to identify the operation and take the right action.

They are like extensions to your IP address. For example, your computer’s IP address is 53.125.105.18, while the file transfer protocol (FTP) port number is 20. Thus, the IP for an open FTP port would be 12.345.678.90:20. By seeing this address, the server will “understand” your request.

Port numbers have different numbers and types. Every different action has its own port so that they can all coexist under the same IP address:

  • Well-known ports (0 to 1023) are used by major companies like Apple or MSN for their services;
  • Registered ports (1024 to 49151) can be assigned to specific services by request;
  • Dynamic or private ports (49152 to 65536) can be used by everyone for private servers and temporary purposes.

TCP vs. UDP

Port numbers have different numbers and types. Every different action has its own port so that they can all coexist under the same IP address:

  • TCP is more reliable as it always must establish endpoints between sending and receiving locations for the connection to happen. It guarantees that packets of data will always reach the addressee. It also tracks data to make sure it isn’t lost, meaning that the data arrives securely and in order. This protocol is used for web browsing or email applications;
  • UDP is faster but less reliable as it does not require an established connection. It also allows data to be sent in the wrong order. It doesn’t check data as thoroughly as TCP, so it is more lightweight and quicker. It is employed for operations where speed is an essential factor, like online gaming, video conferences, etc.

Why do you need to know your port number?

It allows you to have more control over your software. Because applications use specific ports, they should always be open for them to work properly. On the other hand, closing them can improve your security. If one of your apps can’t connect to the internet, you might want to check the relevant port and open or close it.

Firewalls can block some ports, so manually allowing them to bypass firewalls may be necessary.

How to find your port number on Windows

  1. Type “Cmd” in the search box.
  2. Open Command Prompt.
  3. What is my port number

  4. Enter the “netstat -a” command to see your port numbers.
  5. What is my port number

How to find your port number on Mac

  1. Open Spotlight by pressing Command+Spacebar.
  2. What is my port number

  3. Type “network utility” and press enter.
  4. What is my port number

  5. Click on the Port Scan tab.
  6. Enter the IP you wish to scan.
  7. What is my port number

  8. Press scan.
  9. What is my port number

  10. See a list of open ports.

How to open a port on Windows 10

  1. Go to Control Panel.
  2. What is my port number

  3. Go to System and Security -> Windows Defender Firewall.
  4. What is my port numberWhat is my port number

  5. Select Advanced settings.
  6. What is my port number

  7. Click on Inbound Rules on the left.
  8. What is my port number

  9. Click on New Rule on the right.
  10. What is my port number

  11. Choose the Port option.
  12. What is my port number

  13. Choose the protocol (TCP or UDP) and add the port number into the Specific Local Ports section. You can find the list here.
  14. What is my port number

  15. Select Allow The Connection and press Next.
  16. What is my port number

  17. Select what type of network this rule applies to and click Next.
  18. What is my port number

  19. Add a name and short description to the rule and click Finish.
  20. What is my port number

To close the port, simply remove the rule.

How to open a port on Mac

It is very easy to open a port on Mac. Here's how:

  1. Open System Preferences.
  2. What is my port number

  3. Go to Security and Privacy > Firewall > Firewall Options.
  4. What is my port number

  5. Tap plus sign.
  6. What is my port number

  7. Choose an application and click Add.
  8. What is my port number

  9. Make sure that Allow Incoming Connections is turned on.
  10. What is my port number

  11. Click OK.

To close the port, simply remove it from the list.

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Paul Black
Paul Black successVerified author

Paul is a technology and art enthusiast who is always eager to explore the most up-to-date issues in cybersec and internet freedom. He is always in search for new and unexplored angles to share with his readers.


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