Using Firefox with a Transparent Web Proxy

Article #: Product Castle
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You have:

  • Automatic authentication using NTLM
  • Guardian is using transparent authentication policies

To get the Mozilla Firefox® browser working with the above, Firefox needs to be told that sending credentials to the Smoothwall is allowed.


When using Firefox with Guardian NTLM authentication in transparent mode we always get an authentication dialogue prompt — why?


You need to carry out the below procedure on each individual client device that uses the Firefox browser and needs to proxy through Guardian. The client device also needs to be able to resolve the Smoothwall hostnames without any domain information.

  1. Open the Firefox browser and enter the following into the address bar:
  2. about:config

  3. Continue past the warning, then search for NTLM.
  4. In the resulting list, search for the following key:
  5. network.automatic-ntlm-auth.trusted-u">

  6. Edit this key and add the hostname of the Smoothwall to the list.
  7. Multiple hostnames can be entered in a comma- and space-separated list like this:

    guardian1, guardian2

  8. Save and exit.


Last updated: Author: Contributions by:
30 August 2016   Tanja