Why Does Windows Defender Firewall Block Some App Features?

Almost everyone who uses Windows has seen it. You launch an application or game, and Windows Firewall pops up and says it7;s ;blocked some features of this app.; What does this mean, and should you allow access?

Why Does This Message Appear?

This message appears when an application wants to act as a server and accept incoming connections. You don7;t see this prompt for most applications you use, like web browsers and email clients. You only see it with specific types of applications, such as media servers, games with multiplayer features, online file-sharing tools, and other server applications.

The Windows Firewall blocks incoming connections by default. But the first time it blocks connections to a new application, this message pop up. You can then choose whether to allow the connection through. This ensures connections aren7;t silently blocked without your knowledge.

On Windows 10, you see a ;Windows Defender Firewall has blocked some features of this app; pop-up. On Windows 7 and 8, you see the ;Windows Firewall has blocked some features of this app; message instead.

Should You Allow Access?

When this box appears, you have a few choices. You can click ;Allow Access; and allow incoming connections through the firewall. Or, you can click ;Cancel,; and the firewall continues to block incoming connections for that application.

You can also choose which types of networks you want to allow the connections on. For example, you might allow a media server application only on private networks. That way, when you connect your laptop to public Wi-Fi, no one can connect to your media server. People on your home or work networks, however, will still be able to connect.

When you connect to a network, you choose whether it7;s public or private2;Windows doesn7;t automatically know. You can change this option for a network later in the Control Panel or Settings app.

If you trust an application and want to use all its features, you should allow access. If you disallow access for a PC game, you might not be able to host multiplayer games. If you see this prompt and want to use a media server to share your media with other systems on your network, you likely have to allow access to do so. A BitTorrent client, for example, needs this access to upload data to other systems on the internet.

If you don7;t allow access, an application might not function properly. So, you might not be able to host multiplayer games in a PC game, as the firewall blocks incoming connections.

If you don7;t recognize the application, you might want to search the web for the name and find out more information. Some types of malware function as a server and might trigger a firewall alert. Run a scan with your preferred antivirus program if you7;re concerned your PC might have malware.