What you want is something called a WAN failover. There’s a bunch of routers that offer it but I know OPNsense (and pfsense) has it.
First place my mind went for a recommendation - and then discarded for someone w/ their exp level.
I would guess they could set up a pfSense box. Netgate has pretty good online docs. But even after deploying pfSense for 15 years, I still approach CARP (WAN failover) with some trepidation. It doesn't always just go (or stay going).
look at Firewalla. ... it’s so easy even your parents can set it up"
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First place my mind went for a recommendation - and then discarded for someone w/ their exp level.
I would guess they could set up a pfSense box. Netgate has pretty good online docs. But even after deploying pfSense for 15 years, I still approach CARP (WAN failover) with some trepidation. It doesn't always just go (or stay going).
New to me too. It sounds promising.