How to get client IP's from secondary router's DHCP server

Hello there! I have the following setup:
ISP -> OpenWrt (NanoPi r4s) -> Google Wifi

I'm using OpenVpn client mode on OpenWrt and it's working like a charm, and now I would like to add vpn-policy-routing to the mix. It's also working nicely, tested with specific port policy.

The problem:
I can't use IP filters in vpn-policy-routing because they are issued by Google Wifi DHCP server, and honestly, I don't want to change GWifi setup.

Is there a way to ip's from google wifi's DHCP server in OpenWRT?
Or maybe I should do something like this?

Thanks a bunch in advance for any info!

intercept and redirect google wifi DNS calls ?

I just want OpenWRT to know client IP's to use them in policies, Right now Google Wifi has 192.168.86.X and OpenWRT thinks they all are 192.168.2.168

which is correct, since you won't be able to see the IPs of the clients, because they're behind a NAT.

2 Likes

Is there a way maybe to use Google Wifi DHCP for lan instead of OpenWrt one?

Probably, but it wouldn't solve your problem...

As long as your google wifi runs as a router, you will not able to do what you would like to.

You could try to move the WAN cable to the LAN port. If it's smart enough it'll realize it shouldn't
run a DHCP any more, and route the traffic.

Doesn't seem to be supported though https://support.google.com/wifi/answer/6240987

Another option is to put the r4s inside the google wifi LAN, but that's only doable if the
DHCP of the google can be configured or disabled.

1 Like

Thanks a lot for reply! Gonna try anyways, don't want to break existing functionality like mesh and other goodies