The Norton Internet Security software package for Windows includes a firewall component, which controls the programs that can connect to the outside world and the types of connections that they can make. If Norton Internet Security doesn't permit Firefox to connect to the Internet, Firefox generates a "Server not found" error when you try to browse to websites.

Checking for Norton Internet Security

To see if you're running Norton Internet Security's firewall:

1. Open the Windows Control Panel.

• • (Windows Vista) Click the Windows icon, and select Control Panel.
  • (Windows XP) Open the Windows Start Menu, and select Control Panel.

1. In the Control Panel, open the Windows Security Center.

• • (Windows Vista) Under the Security header, click Check this computer's security status.

1. Open the Firewall header. Try to locate the following text:
   Norton Internet Security reports that it is currently turned on
2. If it is displayed, you are using Norton Internet Security's firewall.

Configuring Norton Internet Security

The newest versions of Norton Internet Security should automatically detect and allow Firefox access to the Internet. Older versions, however, may silently block Firefox after it is updated.

To ensure Firefox can access the Internet, you must remove the Firefox entry from Norton Internet Security and allow it to re-detect Firefox. Below are instructions for Norton Internet Security 2009, 2007, 2008, 2002 and Norton Internet Security 2010. Other versions may have variations on these processes.

Norton Internet Security 2009/2010

1. Right click the Norton Internet Security icon in the system tray at the bottom right of your screen. Select Open Norton Internet Security.
2. In the network panel, click Settings. The Network settings appear.
3. Scroll down to Smart Firewall. Click Configure.
4. Select Mozilla Firefox. Then, click Remove at the bottom of the window.
5. In the confirmation prompt that appears, click Yes.
6. Try to access a website through Firefox.

Norton Internet Security 2008

1. Right-click the Norton Internet Security icon (a yellow circle) in the system tray at the bottom right of your screen. Select Open Norton Protection Center. The Norton Internet Security dialog appears.
2. In the dialog, click Options.
3. In the menu that opens, click Norton Internet Security. Another dialog opens.
4. In the dialog, click Personal Firewall. Then, click Program Control.
5. Select Mozilla Firefox. Then, click Remove.
6. In the confirmation prompt that appears, click Yes.
7. Click OK to close the window.
8. Try to access a website through Firefox. If Norton asks you to allow Firefox, you should allow it.

Norton Internet Security 2007

(based on a live chat session, some instructions are predicted)

1. Right-click the Norton Internet Security icon (a yellow circle) in the system tray at the bottom right of your screen. Select Open Norton Protection Center. The Norton Internet Security dialog appears.
2. Choose the Norton Internet Security tab.
3. In the dialog, click Settings.
4. Click "Personal Firewall" and then Configure
5. Select Program Control
6. Select Mozilla Firefox. Then, click Remove.
7. Click Add....
8. Browse to the Firefox executable. This will by default be C:\Program Files\Mozilla Firefox. Choose firefox.exe and press Open. An Internet Access Control dialog will appear.
9. In the dialog, select Allow and click OK. Restart firefox.

Norton Internet Security 2002

1. Right-click the Norton Internet Security icon (a blue/green circle) in the system tray at the bottom right of your screen. Select Norton Internet Security. The Norton Internet Security dialog appears.
2. On the left of the dialog, click Personal Firewall, then click Internet Access Control.
3. Look for Firefox in the list of applications in the center of the screen. If you find it, click on it and press Remove.
4. Click Add....
5. Browse to the Firefox executable. This will by default be C:\Program Files\Mozilla Firefox. Choose firefox.exe and press Open. An Internet Access Control dialog will appear.
6. In the dialog, select Permit this application access to the Internet and click OK. A Choose Application Category dialog will appear.
7. Choose Web Browsers from the list and press OK.

You should now be able to access the Internet with Firefox.

More information

For more information on Norton Internet Security, see Symantec's support site.

Based on information from Firewalls (mozillaZine KB)