TL;DR: How do I redirect all HTTP(S) traffic of connected devices on a self-controlled Linux WiFi Access Point to Apache/nginx on the same machine and let Apache/nginx respond back?
Scenario: I have a hardware device (“D”) which has WiFi. And I have a Linux device (“L”, Ubuntu-based) that spans a Wifi network and D is connected to L. So far so good.
D has the built-in feature to do HTTP requests to some external server owned by the manufacturer (for example to check for firmware updates).
I now want L to act as this external server and fake the response to make D force into thinking there is (for example) a new firmware update.
I do not want a proxy (like mitmproxy) that forwards the requests to the real server or needs heavy manual user-interactions! I know the HTTP headers and body that are needed by D. I just want to directly answer with a forged response to D.
Simplified: D does a GET http://manufacturer-server.com/firmware-version-check and L should answer with a HTTP document forged by me. Then D will do a GET http://manufacturer-server.com/firmware-file-download and L should answer again like I forged it for this new URL.
What tools do I need? Since D is doing only HTTP requests and I can connect it to L, an Apache or nginx would be enough (I don’t want over-complicated setups) to serve a static file for all the external endpoints I need – but how do I get the HTTP server to listen and responds to requests of the connected D? Do I need to fiddle with the DNS?
