How can I successfully enable Windows authentication in Firefox?

Firefox does not support Windows authentication by default without NTLM. You can solve this by either enabling NTLM in IIS Manager (not recommended) or use the following workaround in the Firefox browser.

The workaround for Firefox requires the browser settings to be changed:

  1. Open Firefox and enter about:config in the address bar. Click to confirm advanced configuration.

  2. In the Filter field, enter negotiate.

  3. Double-click network.negotiate-auth.trusted-uris. This preference lists the trusted sites for Kerberos authentication.

  4. Enter your domain (e.g. company.local)

  5. Click Save (the tick button).