So, what's the difficulty in finding the problem ? I do this every day, (well maby not every day but it's a part of my job and those things do happend from time to time).
Her's how to find out what's happening.
1) Install this 'nim' software on a windows machine, let's call it W
2) Verify that you *can't* reach www.fbi.gov.
3) Make a request to a webserver you control and, watch the traffic (there is a undocumented switch -D in tcpdump that gives you the tcp payload in plain text).
4) using ncat,wget or telnet craft a similar request, at you saw in (3) to fbi.gov's webserver.
5) if (4) didn't work, well, then you know that one of the attributes of the requests is to blame, cookie, referer, browser version etc ...
6) If (4) *did* work, then there are 2 possibilities.
a) fbi.gov is giving zeroknowlidge's prox servers a special
b) There is a bug in the 'nim' software, use netcat to serve
FBI's complete HTTP response from your own server.
This does not guaranty that you will find it, but you just
And if you do, well, then you have found it.
p.s. www.fbi.gov works just fine with my JunkBuster enabled Netscape, on my Linux box.