My ISP blocks ICMP so WAN failover doesn't work with OPNsense's default failover settings. Are there any alternatives to ICMP that can be used to detect when a WAN connection goes down and when it comes back?
They're not blocking all upstream ICMP though, right? Can you just set your monitor IP to the second or third hop?
They're known for having failures in some random places and the only upstream hop that ping can be used on is our most local gateway but there's still several more with potential to fail before it leaves the country.