Unable to get transparent proxying working (MacOS Sierra)



Mitmproxy works fine in regular mode, but when I try to run the transparent proxy, no traffic seems to reach my server (running mitmproxy). I’ve followed the guide (http://docs.mitmproxy.org/en/stable/transparent/osx.html) but is still unable to get it to work.

I’m running mitmproxy on my MacBook Pro, and I can connect to this machine from my clients (tested with netcat and other tools). IP forwarding is enabled, and so are the pf rules. Mitmproxy is listening to the correct port (8080), so that should not be the problem. However, when I change the network settings on my clients to use my server as gateway/router, instead of using it as a proxy, the clients lose all network connectivity.

I don’t know how to debug this, so any suggestions are highly appreciated!