We have just installed squid 2.5 on redhat 9 using the default ncsa_auth

Squid seems to be working fine. When a client requests an internet page,
the browser pops up the basic authentication window and on successful
authentication, squid serves the request.
But Im not able to automatically authenticate to squid using the 'url
login' format. ie if I request a webpage using -
http://usernameassword@somesite.com/some_page , the browser still throws
up the basic authentication window (meaning squid was not able to
authenticate me).

What could be the problem. I have tried to encode the username pasword in
the url using base64 but no luck. Btw I have tried using IE6, Opera7 and
Netscape4.7 with all failing in simillar manner.