Enabling Windows Integrated Authentication on Firefox 3 Start Mozilla Firefox 3 or later. Open this URL: about:config On the "This might void your warranty!" window, click "I'll be careful, I promise." Filter on network.automatic-ntlm-auth.trusted-uris. Specify a value in the network.automatic-ntlm-auth.trusted-uris field, for example, https://,http:// More information is available from the Mozilla Developer site: https://developer.mozilla.org/En/Integrated_Authentication