web server access control question

[Sandipan Panigrahi <pani@frontiernet.net>]

Hi, 
I am helping a friend install a web server. He wants this
to be visible from an "intranet" as well as from the outside
world.

But he wants to put in password protection for the pages
for any http requests from outside, but any requests from
the intranet inside should not need any access control.

One way could be to have 2 servers running at different
ports, one configured with security and one without, and
disable access to the "internal port" from the outside
using a firewall.

But is it possible to selectively prompt for a password
depending on the source of the http request ? In any of 
the web servers, apache or netscape or any other. 

Also is it possible to use coldfusion with Apache  ?

thanks,
sandipan