How to Find and Use the Windows 10 Firewall

This article explains how to find and use Windows Defender firewall settings in Windows 10. We have separate instructions for using the Windows 11 Firewall.

Why and How to Access Firewall Options

Windows Defender Firewall offers several settings that you can configure:

• Manually block a program that’s allowed by default, such as Microsoft Tips or Get Office. When you block these programs you, in essence, disable them. If you’re not a fan of the reminders you get to buy Office, or if the tips are distracting, you can make them disappear.
• Opt to let apps pass data through your computer that aren’t permitted by default. This customization often occurs with third-party apps you install like iTunes because Windows requires your permission to allow both installation and passage. But, the features can also be Windows-related such as the option to use Hyper-V to create virtual machines. 
• Turn off the firewall completely. Do this if you'd like to use a different vendor's security suite, like one from our list of free firewall apps. You should disable Windows Firewall if you’ve installed an alternative. Don’t disable the Windows Defender Firewall unless you have another one in place, and don't run several firewalls at the same time.

When you’re ready to make changes to Windows Firewall, search for and open Windows Security from the search bar on the taskbar. All those firewall-related tasks are available through Firewall & network protection.

How to Allow an App Through the Windows Defender Firewall

When you allow an app in Windows Defender Firewall you choose to allow it to pass data through your computer based on whether you’re connected to a private network or a public one, or both. If you select only Private for the allow option, you can use the app or feature when connected to a private network, such as one in your home or office. If you choose Public, you can access the app while connected to a public network, such as a network in a coffee shop or hotel. As you’ll see here, you can also choose both.

Follow these steps to allow an app through Windows Firewall:

1. Open the Start menu, then search for and select Windows Security.

2. Select Firewall & network protection.

3. You'll arrive on the firewall page. Near the bottom are a few options displayed less prominently in smaller font. Select Allow an app through firewall.

4. Press Change settings, and accept the prompt or type an administrator password if asked.

5. Locate the app you want to allow through the firewall. It won’t have a check mark next to it.

6. Select the checkbox(es) to allow the entry. There are two options Private and Public. Start with Private only and select Public later if you don’t get the results you want.

7. Press OK.

How to Block a Program with the Windows Defender Firewall

The Windows Firewall allows some Windows 10 apps and features to pass data into and out of a computer without any user input or configuration. These include Microsoft Edge and Microsoft Photos, and necessary features like Core Networking and Windows Defender Security Center. Other Microsoft apps like Cortana might require you to give your explicit permissions when you first use them, though. This approval opens the required ports in the firewall, among other things. You can withdraw your consent to bypass the firewall, however.

Here's how to block a program from the firewall on a Windows 10 computer:

1. Repeat the first four steps above to access the Allowed apps area of the firewall settings.

2. Locate the app you want to block. It will have a check mark next to it.

3. Select the checkbox(es) to disallow the entry (i.e., you're removing the checkboxes). There are two options — Private and Public. Select both.

4. Press OK to save and exit.

After you’ve completed this process, the apps you’ve selected are blocked based on the network types you’ve selected.

Why Are Firewalls Important?

In the physical world, a firewall is a wall designed specifically to stop or prevent the spread of existing or approaching flames. When a threatening fire reaches the firewall, the wall maintains its ground and protects what’s behind it.

Windows Defender does the same thing, except with data—or more specifically, data packets. One of its jobs is to look at what’s trying to come into and pass out of the computer from websites and email, and decide if that data is dangerous or not. If it deems the data acceptable, it lets it pass. Data that could be a threat to the stability of the computer or the information on it is denied.

It's a line of defense, just as a physical firewall is. This, however, is a very simplistic explanation of a very technical subject.