Don’t want to have to import your root certificates in Firefox in addition to IE? With this setting you can just set Firefox to use Windows’ native certificate store. I seem to need to do this frequently, with all of my reinstalls of Firefox.

Go to Firefox, type about:config in the address bar and hit Enter, agree to the disclaimer, then search for
security.enterprise_roots.enabled and set it to True.

More information here: Mozilla Wiki: Add Root to Firefox

To configure it for NTLM (used in enterprise for authentication on internal networks), this guide has more information (How to Enable Automatic NTLM Auth. First set network.automatic-ntlm-auth.allow-non-fqdn to True, then go to network.automatic-ntlm-auth.trusted-uris and add your domain, such as, “intranet.local, intranet”.