I have a question about transparent proxying. Suppose I have the following rule in my kernel:
iptables -t nat -A PREROUTING -i eth1 -p tcp --dport 80 -j REDIRECT --to-port 3128
The purpose of the rule is that all web traffic is captured by a proxy listening to a local port. Now the question:
How does the proxy get to know the original destination IP address and port? By looking into the HTTP-request, perhaps? If so, what if the application protocol (some other than HTTP) does not contain the destination URL?
Cheers, Mikko
