Redundant physical router with automatic failover?

I currently run a singe Untangle (Arista Edge Threat Management) router/firewall, and I am trying to determine if it is possible to have two separate physical router appliances serving the same network, in a redundant failover capacity?

In the investigations I’ve done so far it seems easy enough using virtualized DHCP servers, but I’m more interested in hardware redundancy, not just software.

I currently have a dual WAN configuration with failover, and could have two separate routers one with each WAN. Maybe that would work, not sure exactly. But Ideally I’d want to run both WANs to both routers.

It crossed my mind to have a third WAN on a backup router, but I’d rather not have to pay for, or manage, 3 WANs.

Any ideas/thoughts would be appreciated. (also not totally attached to Untangle if someone knows how to do this with another OS)

I believe this is supported by pfSense

https://docs.netgate.com/pfsense/en/latest/highavailability/index.html

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pf + carp

carp(4) (also available in OpenBSD)

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Would dns settings also work?

Lets see if i can explain what has come to my mind.

Router 1 with IP address 192.168.0.0
Router 1 with IP address 192.168.0.1

on the managed switch / pfsense box /internal network devices set the dns setting to point to the ip address of each of the routers and set the dns severs on the routers to the isp supplied / or your preferred dns service.

You can also run both WAN to both routers using a managed switch between the ISP uplink and the routers then setting VLAN to isolate the WAN’s.

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Many large corporations have multiple physical routers with multiple WANs being distributed to each router for failover. You’ll learn this network design in CCNA. And yes you can do this in pfsense.

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That makes sense in so far as it is doable, but it has the same problem as a single router. There is a single point of failure device, which is ultimately what I am trying to avoid.

this is the way to go, they create a Virtual IP who stay the same no mater which router is being used, and all state and config are automatically sync between the device

You can also have both Uplink connected to both router in order to independent uplink fail-over and router fail-over

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This is interesting. I would need a lot more switches to implement the diagram. But I wonder if the routers themselves could function as both the top level switch and the router?

Good video, gave me some ideas, but didn’t talk much about what specifically is needed in the software to configure the 2/3 tier architectures or the redundant devices.

This is very interesting, but seems complicated. I’d have to do more reading to figure out if this will work with all my devices, but thank you for the link! This is great to know about!

This is good stuff, very well could be the answer I need. Migrate to pfSense. Thank you for the link!

That’s also what pfsense uses fwiw, pfSense® software Configuration Recipes — High Availability Configuration Example | pfSense Documentation

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