transproxy - transparently proxy HTTP and other requests.

This program is used with Darren Reed's IPFILTER package and used
to intercept things like http requests and divert them to a www proxy
server (eg: squid), without requiring user intervention or configuration.

It accepts connections on the redirected port, connects to the real proxy
server and transports data between the two sockets.

Unlike some other transparent proxy solutions, this does not require the
proxy run on the machine itself.

Use something like:
/usr/local/sbin/tproxy -b 127.0.0.1 -s 8081 [squidip] [squidport]

(bind to localhost for safety), and the following ipnat rules:

rdr ppp0 0.0.0.0/0 port 80 -> 127.0.0.1 port 8081
rdr ppp1 0.0.0.0/0 port 80 -> 127.0.0.1 port 8081
[..etc..]