How to redirect all traffic through a proxy without a loop?

[FarelRA]

I want to redirect all traffic from my apps and programs (including those that do not support proxies or VPNs) to a local HTTP/SOCKS proxy server, which will then redirect the traffic to an online proxy server.

I created the following network topology:

However, I want to avoid creating a loop, where the local proxy server redirects traffic to the redirector, which then redirects it back to the local proxy server.

 

[jpnilson]

Check into using a via header. Outbound the header is added and checked for on the way back in. If it exists the packet is discarded

 

[vs2-free-users]

I think you can use iptable prerouting table for this. You must configure it on the router. Example(10.0.0.1 is the ip of the proxy server):

iptables -t nat -A PREROUTING -p tcp --dport 80 -j DNAT --to-destination 10.0.0.1:80
iptables -t nat -A PREROUTING -p tcp --dport 443 -j DNAT --to-destination 10.0.0.1:443