'Preventing' HTTP Tunneling (cont)

$ perl -MMIME::Base64 -le 'print encode_base64("reegen:twins")'
cmVlZ2VuOnR3aW5z

$ nc proxy 3128
GET http://www.example.com/ HTTP/1.0
Proxy-authorization: Basic cmVlZ2VuOnR3aW5z
User-Agent: Mozilla/3.01Gold (X11; I; HP-UX A.09.05 9000/770)

HTTP/1.1 200 OK
Date: Thu, 25 Sep 2003 20:30:00 GMT
Server: Apache
Content-Length: 5773
Connection: close
Content-Type: text/html; charset=iso-8859-1
X-Cache: HIT from client.host_name.com
Proxy-Connection: close
...