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Enable NTLM Single Sign On in Firefox

G14th May 2018

C1 Comment


A simple procedure for enabling Single Sign On (SSO) in Firefox.

NTLM (NT LAN Manager) is a suite of Microsoft protocols that provide authentication, integrity and confidentiality for users. Although Microsoft has adopted Kerberos in modern versions of Windows server, NTLM is still used when authenticating to a workgroup. Those who use Firefox in a corporate environment will notice that they are prompted for a username and password when using internal web applications whereas Internet Explorer and Edge allow immediate access via Single Sign-On (SSO).

Firefox is also capable of NTLM SSO authentication. Here is the procedure for setting it up:

Step 1

Using the Firefox address bar, enter about:config. Click the “I accept the risk!” button.

Screen capture of the "I accept the risk" dialogue in Firefox.

Step 2

Use the search bar to locate network.negotiate-auth.trusted-uris. Double-click on the result.

Screen capture of the about:config window in Firefox

Step 3

Enter the URLs or domains of the websites for which you want to enable NTLM SSO, as a string and separated by commas. Do not add trailing slashes. Inclusion of the protocol is optional.

An example:


Screen capture of Firefox dialogue box

Press OK.

Step 4

Restart Firefox.


There are actually several options for enabling Single Sign On in Firefox:

  • network.negotiate-auth.trusted-uris lists the sites that are permitted to engage in SPNEGO authentication with the browser.
  • network.negotiate-auth.delegation-uris lists the sites for which the browser may delegate user authorisation to the server.
  • network.automatic-ntlm-auth.trusted-uris lists the trusted sites to use NTLM authentication.


One response to “Enable NTLM Single Sign On in Firefox”

  • Written by Coutes on 17 January 2019:

    Thank you for your article, clear and usefull for us.

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