How do I use firewall to stop internet connection of an application?

It's always a good idea to keep an eye on which apps have online access. Restricting or revoking internet usage for certain services is a good way of making your device more secure and keeping your personal information private.

Do you want to block an app from accessing the internet on your Windows or Mac computer? Let's explore how you do just that on your PC or laptop.

Why Prevent Apps From Accessing the Internet?

There are various reasons you may want to block an app from accessing the internet.

It might be that you’re suspicious of a service and you are not sure what data it shares with the developer when you let it connect to the internet. Keeping an eye on what personal details are shared is always a good move.

Another possible reason is that you don’t want your kids to access certain online content in some apps. In this case, blocking the internet for your apps is really helpful.

How to Prevent Apps From Accessing the Internet on Windows

If you use a Windows PC, you don’t need to install an app to block online activities for your apps. Your built-in Windows Defender Firewall is capable enough of letting you restrict certain apps from using your internet connection.

Block the Internet for an App in the Windows Firewall

To use the firewall to restrict the internet, you need to create a rule in this utility that blocks the internet for selected software. Here's how to create this rule:

1. Open the Control Panel, click System and Security, and then Windows Defender Firewall.
2. On the left, click the option that says Advanced settings to view the advanced firewall settings.
3. Select Outbound Rules on the left as you’re creating a new outbound firewall rule. Then, click New Rule on the right..
4. The firewall should ask what kind of rule you want to create. Select Program and hit Next at the bottom.
5. On the resulting screen, choose This program path and click Browse.
6. Find the app that you want to prevent from connecting to the internet. Once you see the app’s EXE file, click the address bar in File Explorer and press Ctrl + C to copy the folder path. Don’t select the EXE file just yet.
7. Get back to the firewall panel and paste the copied path in This program path. Then, enter the name of the EXE file (Ctrl + V). You need to do this because Windows doesn’t automatically use the absolute path to your app’s executable file. Then, click Next.
8. Select Block the connection and click Next.
9. Tick all options and click Next to ensure the app is blocked from accessing the internet no matter the situation.
10. Enter a name for your rule; this will appear in the rules list. You can add a description if you want to and click Finish.
11. Your newly created rule should now be running.
12. Launch your app and you’ll find it can’t access the internet anymore.

Unblock the Internet for an App in the Windows Firewall

If you ever decide to allow your blocked app to access the internet again, you can do that as follows in your firewall:

1. Search for Windows Defender Firewall with Advanced Security in the Start menu, and click it.
2. Click Outbound Rules on the left to view your outgoing connection rules.
3. Find the rule you created earlier on the right and select it.
4. Click Disable Rule on the right to turn the rule off. This will allow your app to connect to the internet.
5. If you won’t be using this rule anymore, click Delete to get rid of it for good. Be certain before you take this step.

If you want to give temporary internet access to your app, you should disable the rule instead of deleting it. Then, when you want to enable the block again, you can turn the rule on.

Prevent Apps From Accessing the Internet on macOS

MacOS has both built-in as well as third-party methods to block apps from accessing the internet.

However, the macOS firewall only allows you to block incoming connections for your apps (and to do this, you'll need to know how to set up macOS firewall). Unless this is what you want to do, you need to go for the third-party app method.

Use an App to Block Internet Access for Your Mac Apps

There are several apps to help you block the internet for your apps on your Mac. One of these is Radio Silence (free trial, then $9 one-time fee) that helps you block and unblock the internet for your apps in a few clicks.

You can use some browser extensions to block certain websites, including temporary and long-term solutions.

Here we show how you use this app to prevent internet access for your installed apps on macOS:

1. Download, install, and launch Radio Silence on your Mac. You need to download the app from its website as the app isn’t available on the Mac App Store.
2. Click the Firewall tab on the main app interface.
3. Click Block Application in the bottom to add an app to the list.
4. Navigate to the app that you want to restrict internet access for. Usually, all your apps are available in the Applications folder.
5. The internet is now blocked for your app.
6. You can enable and disable the functionality of Radio Silence by using the toggle in the bottom-right corner.

Use the macOS Firewall to Block Incoming Connections

If you’re only looking to block the incoming connections for your apps, the built-in macOS firewall should be sufficient. Here’s how you use it:

1. Click the Apple logo in the top-left and select System Preferences.
2. Select Security & Privacy.
3. Click the Firewall tab and select Firewall Options.
4. Click the Add (+) button and add the app you want to block incoming connections for.
5. Choose Block incoming connections from the menu next to your app in the list.
6. Hit OK in the bottom to save your changes.

Give Internet Access Only When It's Needed

Not all apps on your computer need to connect to the internet to function. If you don’t want an app to send data online, the methods above help you block that service from getting access to the outside world. Make sire you're not limiting any core functionality by revoking this, however!

There are a few other measures as well that you can take to protect yourself from being spied on by apps that might otherwise seem trustworthy.