OpenWrt, wireguard and metrics

[Enrico Mioso]

Hello All!!

first of all, I would like to express once again my gratitude for your great work. OpenWrt is, as you may know by now, one of my favourite projects.

So, I have a kind of rudimentary multi-wan setup: an FTTC connection via PPPoE is used as the main one, with 5G link as fallback.
Main router is at 192.168.2.1, while 5G is 192.168.2.15.
So the 5G router is a separate device, reachable via LAN by the main router. I wanted to keep things really simple, so I simply added a route pointing to the 5G device as a default gateway, altough with an higher metric.
This setup kinda does what I want:
- connections go out from the PPPoE link (wan interface in the main router)
- if the wan interface goes down, traffic goes out from 5G link.

But then, things get complicated. I had two main issues:
a - DNS: of course, once the wan interface was down, it's DNS where removed. I solved that by adding some other DNS servers to the LAN interface, obtaining the desired effect (even tough I expect there is a more elegant solution here).
b - The main router acts also a wireguard gateway. What I am observing here is that wireguard will always prefer 5G link, while I would like it to respect the metrics.
I can also see it creates a route to my wireguard endpoing via the br-lan interface pointing to the 5G device. Removing that route manually seems to fix my problem, but wondering if I can prevent it from being created in the first place.
I tought I could use the wireguard "nhostroute" option for this, but it seems not the case.

Am I doing things completely the wrong way? Or is there any solution I may try out?


Thanks,
Enrico