OpenWrt won't assign Ipv4 address to iPhone

[Meceleste0]

So this is a multi-part question and it is complicated by some annoying things about my network topology. I will give a verbose question, but one can skip to the bottom and read the following details as needed.

I have a router on, say, 192.168.1.1/24 not running OpenWrt and NOT running a DHCP server. It connects to a computer on 192.168.1.2/24 which runs a DHCP server and dns requests route through this device.

I recently installed OpenWrt firmware on a spare router and intended to use it as a repeater to increase coverage for the 192.168.1.1 router. I attempted to configure it myself however after much frustration I reset the device's settings and followed this guide: https://openwrt.org/docs/guide-user/network/wifi/relay_configuration to the letter. I succeeded in giving my OpenWrt device it's own subnet 192.168.2.0/24 and make a bridge relay device which listens on 192.168.1.3. The router could ping websites when configured this way so all seemed well, and I could access the Luci GUI by navigating to the ip of the bridge in a web browser.

Now the problems started:

1.) I noticed that the signal strength on my iPhone wasn't particularly strong so I attempted to disconnect and reconnect it to the wifi network, disaster! Now it can't seem to find an ipv4 address and shows up as 169.* on the network. When I try to manually assign it an ipv4 address on the iPhone's network settings it still can't connect. There were no such problems before I configured my repeater.

2.) I fussed around a bit in the OpenWrt router settings to see if something might be wrong (e.g. incompatible encryption or bad channel settings, etc.) really just pawing around in the dark due to my limited networks knowledge. I saw a setting called something like "enable upstream ipv6 forwarding" on the wwan network interface and decided to uncheck this on the hopes that it would at worst not change anything (the repeater and the host network are only meant to assign ipv4 addresses). Disaster again! When I saved this configuration my OpenWrt device became completely inaccessible via ssh or the Luci interface. I can still see the bridge device at ..***.3 where it should be but all ssh requests to it time out.

First: can someone explain to me why changing this seemingly inconsequential setting caused my router to go dark on me? This seems to happen quite often when I reconfigure its settings and it's a HUGE PITA to connect via ethernet on its subnet and reconfigure it every time I change anything.

Second: does anyone have any idea what might be going on with the first problem, i.e. why adding the router as a network repeater caused my iphone and other small network devices to be unable to connect to the network as a whole?

[psherman]

Relayd is basically a hack, and it has many potential downsides including issues with DHCP.

Is there any possibility that you can use a wire to connect your OpenWrt router to the upstream network? This will make it possible to use a simple ‘dumb AP’ mode which will perform far more reliably.

[Meceleste0]

It would be very inconvenient, I'm trying to set up this network on different stories of an old european house and it would require an absurdly long Ethernet cable to pass through a very small spiral staircase.

Moreover for my own edification I’d be interested in trying to troubleshoot the functioning of the device as is.

[psherman]

Another option may be powerline adapters which can use your existing mains wiring. Ymmv, though, in terms of performance.

[Meceleste0]

Yes this was the first solution I tried. However the signal was quite poor and the connection was intermittent.

[psherman]

Do you have any other options that might work — for example, coax cabling can be used with MoCA adapters, and those often work pretty well.

[Meceleste0]

The wiring on the upper floors of the house are quite primitive, and I'd be very worried about adding to the wiring infrastructure as some of it is configured quite poorly (have already had some unpleasant surprises). I would really like to be able to have a software/scripting-based solution to this problem. I have confirmed by giving the relevant devices static ip addresses and manually configuring their dns server that the problem is indeed that the DHCP protocol and DNS requests are managed by a third device which is not the router, and all devices connect just fine once these were configured manually (however I'm not sure they're routing through the repeater based on the reported signal strength).

[psherman]

You may actually be best served by purchasing a purpose built repeater device and using the vendor provided firmware (and not OpenWrt) since those devices tend to be a bit more reliable in this mode (they may use relayd or other similar techniques, but if they are purpose-built, they may also have proprietary code on specific chipsets to achieve the required functionality).

[Meceleste0]

Thanks to your moral support I managed to troubleshoot the problems (poorly configured firewall, DHCP assigned another device the wwan's ip which meant the relay bridge was listening on a different ip. Getting DHCP to work through this connection is still hopeless). I appreciate what you're saying but it was important for me to fix this with the kit I had on hand rather throwing money at the problem and buying something with proprietary firmware.