[Ovmsdev] Disabled DNS & router offer on AP DHCP

[Michael Balzer]

Everyone,

please test: following a user suggestion I've disabled the DNS and routing (gateway) offer sent by the Wifi AP DHCP server.

Important: you also need to update the esp-idf from our repository, as the standard DHCP server has a bug that prevents disabling the DNS offer.

This allows devices capable of standard network routing to connect to the OVMS AP without losing their internet connectivity (e.g. provided by cellular
network), potentially solving the issue of the OVMS not acting as an internet router for AP clients.

iOS supports this.

Android apparently doesn't support this. As soon as it connects to any AP, it routes everything over that interface, ignoring missing router or DNS
announcements. You can manually tweak the routing, but only on a rooted device. If anyone knows a trick to do this with an unrooted Android, please tell.

There is an option to bind to a specific network interface. That's meant to support specifically Apps needing to connect to a Wifi network without internet
access without losing the cellular connection. That could mean we can create our own browser App that binds to the OVMS wifi network. Will depend on the browser
component also using that binding for all successive connections though.

Regards,
Michael

-- 
Michael Balzer * Helkenberger Weg 9 * D-58256 Ennepetal
Fon 02333 / 833 5735 * Handy 0176 / 206 989 26