Use external DHCP server with Nighthawk M5

[DebugBug]

The Nighthawk M5 built-in DHCP server does not support IP address reservation, so I have connected a Raspberry Pi with a DHCP server to the ethernet port and disabled the built-in DHCP server. But I cannot make it work, it seems like the DHCP server requests from the wifi connected clients are not passed to the DHCP server on the ethernet port.

Has anybody found a way to either reserve IP adresses with the built-in DHCP server or use an alternative DHCP server connected to the ethernet port?

Seems incredible to me that the most expensive 5G router on the market does not have a simple feature like DHCP IP address reservation...

[plemans]

Your kind of caught. The M5 needs a dhcp server for its wireless to assign ip addresses. 
yes the pihole is supposed to handle it. 

If it was me? I'd use the M5 in passthrough mode and simply connect a router to it. 

It'd act as a modem only device. The router you connect would have better wifi coverage (and speed) and you could use IP reservations. Plus the pihole should work with the router fine. 

[DebugBug]

@plemans it is the pihole DHCP server I have been trying to use on the rPi connected to the ethernet port - but for some reason, it seems the DHCP requests are not routed from the wireless interface to the ethernet port. However, the pihole DHCP server can see the wifi clients with their IP adresses, assigned by the M5.

Not sure if this is a bug in the M5 routing or if it's by design? But it seems strange that I would potentially have to get a wireless client with a DHCP server on it connected to the router in order for it respond to DHCP requests.

Sure, I might have to install an extra Wifi router, but it just seems like overkill as the M5 should be able to do it. It's a pretty expensive 5G modem, if that's all its good for.

[plemans]

For sure could be a bug. Most people are either using the dhcp server built in or using passthrough and letting a different device manage routing. 

I've never tried it with mine to see what impact it has. 

Maybe @JohnPeng has