Configure Windows Firewall to allow Firefox access to the Internet

Windows provides a built-in firewall, which controls how programs access the Internet. If Windows Firewall doesn't permit Firefox to make connections, Firefox generates a "Server not found" error when you try to browse to websites.

Windows 7

Checking for Windows 7 Firewall

To see if you're running Windows Firewall:

1. Click the Windows icon, and select Control Panel. The Control Panel window will appear.

   

2. Click on System and Security. The System and Security Panel will appear.
   
   
3. Click on Windows Firewall. The Windows Firewall panel will appear.
   
   
4. If you see a green check mark, you are running Windows Firewall.
   
   

Configuring Windows 7 Firewall

If you're running Windows Firewall and having connection problems in Firefox:

1. On the left side of the Windows Firewall panel, click Allow a program or feature through Windows Firewall. The Allowed Programs panel will appear.
   
   
2. Click the Change Settings button.
   
   
3. Find Mozilla Firefox in the list of programs. If it is there, click to select it. If not, skip the next step.
4. With Mozilla Firefox (or firefox.exe) selected, click the Remove button. Confirm that you want to remove the entry.
5. Click the Allow another program... button. The Add a Program window will appear.
   
   
6. In the Add a Program window, click the Browse... button.
7. Navigate to the Firefox program directory (e.g. C:\Program Files\Mozilla Firefox\) and double-click on firefox.exe.
8. Click the Add button.
9. Click the OK button to close the Allowed Programs panel.

Windows Vista

Checking for Windows Vista Firewall

To see if you're running Windows Firewall:

1. Click the Windows icon, and select Control Panel. The Control Panel window will appear.
2. Click on the System header. The Security Panel will appear.
3. Click on the Windows Firewall header. The Windows Firewall panel will appear.
4. If you see a green check mark and the message Windows Firewall is helping to protect your computer, you are running Windows Firewall.

Configuring Windows Vista Firewall

If you're running Windows Firewall and having connection problems in Firefox:

1. On the left side of the Windows Firewall panel, click Allow a program or feature through Windows Firewall. The Windows Firewall Settings window will appear.
2. Find Mozilla Firefox (or firefox.exe) in the list of programs. If it is there, click to select it. If not, skip the next step.
3. With Mozilla Firefox selected, click the Delete button. Confirm that you want to delete the entry.
4. Click the Add program... button. The Add a Program window will appear.
5. In the Add a Program window, click the Browse... button.
6. Navigate to the Firefox program directory (e.g. C:\Program Files\Mozilla Firefox\) and double-click on firefox.exe.
7. Click the OK button to close the Add a Program window.
8. In the Windows Firewall Settings window, click to select the General tab.
9. Ensure that Block all incoming connections is not selected.
10. Click the OK button to close the Windows Firewall Settings window.