Sat Sep 22, 2018 3:54 pm
To understand it: in L2TP/IPsec the router does not "push the gw", it is the client that decides to "use the VPN peer as default gw".
Usually you can turn that off in the client, but I don't think that is even possible in Android VPN (it is some months ago I set it up).
Anyway, once you would turn off that option you would have to add routes for some specific subnet(s) and that would be the next problem...
Indeed OpenVPN normally would provide that function, but in the case of the MikroTik OpenVPN that is not possible either.... (very limited version)
So you are really out of luck here. About the only thing that can work is a bare IPsec configuration with IKEv2 with policy setup for the subnets you want to route.
But I think Android can only do that with certificates, so there is a little bit of studying ahead.
(how to generate/install certificates that are trusted on the client)