Wednesday, December 9, 2009

NTLM Active Directory Integration in Firefox

At work we use Active Directory to authenticate our internal websites. This is great if you're using Internet Explorer because it will pass through to the application without requiring further authentication. However, on Firefox you're required to make some changes to get this to work.

Open Firefox and go to about:config

Filter on "auth"

Set all booleans to true

Set network.automatic-ntlm-auth.trusted-uris to a comma separated list of domains that you want AD to do pass through authentication on.

That last instruction never used to work for me. I used to put in the full domain name but for some reason it didn't like it. I've now learned that you only need to put in the trailing part of the domain (TLD/Top Level Domain) and it will authenticate all domains and sub-domains for you.

Say you work for IBM and your internal domains follow a pattern of - all you need to do is add "" to the trusted-uris setting and it will work for you. In fact, all you need to add is ".ibm".

Another thing I often need to do is connect to a site by IP. This will also work by dropping in the last octet of the IP into this list. e.g. ".164" (Obviously you could cover all IP addresses by dropping in all possible 256 octets.)

Here is how to generate all the octets using PowerShell:

$numbers = 0..255 | %{".{0}" -f $_}
$octets = [string]::join(",", $numbers)


  1. O. M. G. Thank you!

  2. Thanks for the tip, I was manually adding all internal website to the config and it was a pain. I added only the domain name now so everything get authenticated with AD credential.
    Thanks for the tip !