Transparent proxy through router?

Question

linux

Actually I was trying to do something similar.
There is a tp link wr740n router put dd-wrt firmware on it.
There is a laptop with windows 7 and fiddler as a proxy server.

Problem:
Tried so that all devices connected to the network would first pass traffic through the fiddler. That is, for example,
a phone with an application sends requests to the router to the computer and back to the router and to the Internet already.
Well, or at least not all devices, but certain ones.
I found some instructions related to ip tables and did not lead to anything.
Can anyone advise on this matter?

Answer 1

I explain the logic.
192.168.10.1 - ip of the router
192.168.10.5 - ip of the computer with fidder. Proxy port for example 8080
On the firewall of the router, you allow traffic to exit on ports 80 and 443 to the Internet only with ip 192.168.10.5.
On the firewall of the router, you turn all traffic except for ip 192.168.10.5 with destination port 80 and 443 to ip 192.168.10.5:8080.
As a result, traffic from any clients to web services 80(http) and 443(https) reaches the router, turns to the fidder, turns from the fidder to the router and enters the Internet. In this case, access to all other ports will occur directly through the router, bypassing the fidder.
PS don't forget to change the dd-wrt webmord to another port =D