IIS uses Integrated Authentication and by default IE has the ability to use your windows user account…but don’t worry, so does Firefox but you’ll have to make a quick configuration change.
1) Open up Firefox and type in about:config as the url
2) In the Filter Type in ntlm
3) Double click “network.automatic-ntlm-auth.trusted-uris” and type in localhost and hit enter
4) Write Thank You To Blogger
As Always, Hope this helped you out.
Source: Pete Orologas