I have 2 different home internet connections and I have an IP from each router's LAN (such as 10.0.0.2/24 and 10.0.1.2/24 with each ISP's routers being the .1) configured on my private server, which then distributes internet access to my network.
The problem is when one of my ISPs goes down I have to manually change my default gateway from 10.0.0.1 to 10.0.1.1 because those IPs are set in each router and the routers are not in bridge mode. Since the downtime has nothing to do with the routers at my home there's no way my server can know the routing table is down because the router is still answering ICMP packets.
The question is, does the Linux kernel support setting to check an IP through a gateway and using the state of that route to also change my gateways? For example, if I were to set 18.104.22.168 to always go through 10.0.0.1 and if that IP stopped responding then bring down the 10.0.0.1 default route as well, that'd work for me.
I know for a fact setting both my routers to bridge mode and letting my server do the PPPoE handshake would work best and avoiding having to do this but at least one of my routers doesn't support bridge mode.