Mass ask authentication in Firefox use NTLM

you can use one of these options

http://blogs.wdevs.com/shog9/archive/2005/03/09/2668.aspx

1. In Firefox, type about:config into the address bar and hit enter. You should see a huge list of configuration properties.
2. Find the setting named network.automatic-ntlm-auth.trusted-uris (the easiest way to do this is to type that into the filter box at top).
3. Double-click this line, and enter the names of all servers for which NTLM is desired, separated by commas. Then press ‘OK’ to confirm.
4. Open the options dialog (Tools->Options menu), and on the General page press the Connection Settings button to get the proxy configuration dialog:
5. Make sure the correct proxy server is configured, and that the same list of servers are listed in the No Proxy for: entryfield as were set in step #3.
6. Done.

http://www.spreadfirefox.com/node/1197

1. Goto to url: about:config

2. filter on NTLM

3. You will see and entry :

network-automatic-ntlm-auth.allow-proxies

4. Set it to false.

5. Close Firefox.

6. Restart Firefox