Multi-wan failover watchguard
I didn't put this in the multi-wan section of the forums because it's not for pfsense. I just happen to respect the advice given on these boards.
The office of our sister company recently purchased a watchguard xtm 26 running the Pro version of the OS for multi-wan support. They have a primary cable internet connection and backup wireless broadband connection.
The failover/failback works fine with the backup wireless broadband for both link failures and default gateway failures (the watchguard monitors link and pings the default gateway by default).
The primary cable internet it detects link failures fine but the default gateway is the cable modem itself (it is a public ip address in the 96.x.x.x so must be something to do with how cable modems do bridging). As a result if I disconnect the coax attempting to trigger a gateway failure it never actually sees a problem because the default gateway still responds to pings.
Fortunately you can configure a different IP for it to ping and/or a different IP/port for it to attempt a TCP connection. So I did a traceroute and tried a couple IPs further down the line but none of them respond to pings/icmp.
I don't want to just pick some random IP to have it ping constantly. Any recommendations on how to go about finding a suitable IP? A quick internet search found a lot of mentions of companies using google's primary public dns server @ 126.96.36.199. Anyone else doing so or should I try to find something inside the cable company's more local network?