What are the risks of allowing apps through a firewall?

There are two ways to allow an app through a firewall. Both of them are risky:

  • Add an app to the list of allowed apps (less risky).

  • Open a port (more risky).

When you add an app to the list of allowed apps in a firewall—sometimes called unblocking—or when you open a firewall port, you allow a specific app to send info to or from your PC through the firewall, as though you drilled a hole in the firewall. This makes your PC less secure and might create opportunities for hackers or malware to use one of those openings to get to your files or use your PC to spread malware to other PCs.

Generally, it's safer to add an app to the list of allowed apps than to open a port. A port stays open until you close it, but an allowed app opens the "hole" only when needed.

To help decrease your security risk:

  • Only allow an app or open a port when you really need to, and follow the steps to remove apps from the list of allowed apps or close ports that you no longer need.

  • Never allow an app that you don't recognize to communicate through the firewall.

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To remove an app from the list of allowed apps

  1. Open Windows Firewall by swiping in from the right edge of the screen, tapping Search (or if you're using a mouse, pointing to the upper-right corner of the screen, moving the mouse pointer down, and then clicking Search), entering firewall in the search box, tapping or clicking Settings, and then tapping or clicking Windows Firewall.

  2. Tap or click Allow an app or feature through Windows Firewall.

  3. Tap or click Change settings. Administrator permission required You might be asked for an admin password or to confirm your choice.

  4. Clear the check box next to the app you want to remove from the list of allowed apps, and then tap or click OK.

To close a firewall port

  1. Open Windows Firewall by swiping in from the right edge of the screen, tapping Search (or if you're using a mouse, pointing to the upper-right corner of the screen, moving the mouse pointer down, and then clicking Search), entering firewall in the search box, tapping or clicking Settings, and then tapping or clicking Windows Firewall.

  2. Tap or click Advanced settings. Administrator permission required You might be asked for an admin password or to confirm your choice.

  3. In the Windows Firewall with Advanced Security dialog box, Tap or click Inbound Rules.

  4. Select the rule that you want to disable, and then, in the right pane, tap or click Disable Rule.

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