Windows Authentication Pass-Through in Firefox

In the last blog post I wrote, I talked about Windows authentication in IIS Express. That was actually the first step in a process I've been working on to use Visual Studio Code as my primary IDE at work. Enabling Windows authentication, means that when I launch a web browser, I can automatically authenticate with the applications I'm developing.

There is a second step to this, though, since I use Firefox as my primary browser at work and at home. Have you ever enabled Windows authentication, but when you launch Firefox, it asks you to login with an authentication prompt? Even worse, you enter in your credentials, and it still doesn't work? It can be a pain, luckily there are a handful of configuration changes you can make to enable authentication to pass through without having to log in.

To make these configuration changes, use the following steps:

• Type about:config in the address bar in Firefox
• Set network.automatic-ntlm-auth.trusted-uris to http://localhost
• Set network.negotiate-auth.delegation-uris to http://localhost
• Set network.negotiate-auth.trusted-uris to http://locahost
• Set signon.autologin.proxy to true

Restart Firefox when you're done. Now when you attempt to launch a locally built application that has Windows authentication enabled, Firefox should no longer prompt you for your information.