How to Check for Open Ports

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Aimie Qual
July 18, 2017 (Last Updated: ) | Reading Time: 3 minutes

To successfully open a port you should first understand a few basics.

The Internet uses what are known as IP Addresses to send data back and forth. Each device on your network has its own local IP address similar to a telephone number. Think of your computer as a large building with many different offices. The building itself has one telephone number. Each office in the building has an extension. Think of the ports as the offices or extensions in that building.

Each application on your computer has a specific port it uses. Email uses port 25, web browsers use port 80, etc... For a list of commonly used ports check out this link. Every application uses these ports so the receiving computer, game console, or device knows which application it needs to use in order to open the data package.

Devices on a home network
Devices on a home network

Open Port vs. Closed Port

An open port is a port that is ready and listening for data on both ends of the line. This means for a truly open port it needs more than for me to just call you. You have to have someone on the other end pick up the phone. Having an open port means your computer has a program to open the data or answer the call.

A closed port is a port that does not have a program on the other end of the line listening. This is because your router doesn't know what to do with the call or incoming connection request. Your router automatically keeps all of your ports closed for you by aggressively rejecting the call or simply dropping the call or packet. It needs to do this because it doesn't know where to send the incoming packet. Your router has no way of knowing which computer or device on your network the incoming packet is destined for. A port forward tells your router who should receive the incoming connection request.


Is it Safe

Having an open port sounds scary, right? A logical question to ask is if it's safe. We have a guide that goes into detail about this exact issue titled Is Portforwarding Safe?

To answer that question in short:

How Do I Open a Port

When you open a port you are forwarding a port. As you know this website is all about Port Forwarding. All you need to do is find your router in our growing list of routers and follow the instructions.

Would you rather have us open the port? If you want to just open ports with a click of a button take a look at Network Utilities. This software opens the ports you want and closes the ports you don't want with just the click of a button.

Is My Port Open

To check if your ports are open simply use our Open Port Checker tool. Our Open port checking tool is better than the others out there because we don't make assumptions about applications you may be using. Our open port tool uses a local application to see if the port is listening. Open Port Checker is part of our Network Utilities bundle of software tools. Check it out here.

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