Run proxy server on iOS

For an enterprise application I want to run a proxy server continuously locally on iOS. Steps I have taken so far:

1. Use NEPacketTunnelProvider to create a tunnel
2. Tunnel the traffic to 127.0.0.1:8080
3. Start Proxy Server from the network extension (this works!)

Step 3 works, however, it seems like after starting up it stops working. I could imagine this having to do something with not being able to run such a process continuously. Does anyone have an idea or a pointer?