Do you have an Intranet or a similar web site that requires the use of Integrated Windows Authentication? If so the default Firefox browser settings will always prompt you for a username and password first before accessing a site using Integrated Window Authentication.

Fortunately Firefox has the slick ability to easily modify it’s configuration to use Integrated Windows Authentication.

How to configure Firefox

  1. Open Firefox
  2. In the address bar type: about:config
  3. Firefox3.x and later requires you to agree that you will proceed with caution.
  4. After the config page loads, in the filter box type: network.automatic
  5. * Modify network.automatic-ntlm-auth.trusted-uris by double clicking the row and enter or http://your-intranet-server-name
  6. * Multiple sites can be added by comma delimiting them such as,

Package for Large Installs

If you are a network administrator that has a lot of installs to do, you can modify the Firefox installer.

  1. Use a tool such as 7-zip to extract Firefox Setup 2.x.x.exe
  2. Extract browser.xpi from the setup
  3. Edit all.js contained in browser.xpi contained in binjreprefs
  4. Modify the entries as in items 4 and 5 above
  5. Re-package browser.xpi and use the extracted setup to install Firefox

* Special Notes

To specify all subdomains use instead of,,

Updated March 5, 2010