Home Networking

That’s a router/firewall job, not a switch job.

https://youtu.be/Fg8GRRUfUVw?si=nI9Y4zkEE3wOiZ-Q

Check this guy out. Might help

Get a TP-Link ER605 multi WAN router which is designed to do load balancing or failover with multiple WAN inputs.

Araknis has one that can do this

I can’t think of a way to do it with an unmanaged switch because, if I’m understanding correctly, it’s going to be a routing issue.

I think you need a router in the middle so that your entire home subnet has the same gateway. Then, when one of the uplinks goes down you don’t have to change gateways on anything but the primary router.

Look for a router with multiple wan ports. I used a Luxul XBR-2300 for this style setup for years. My current Araknis AN-310 will do up to 3 Wan ports for fail over. It really depends on how much you're willing to spend.

Got an old computer sitting in a corner somewhere? Add a multi-port network card and set up Opnsence. Haven’t done it myself, but there are multiple web pages describing how to do just this.

synology routers do this OOTB.

This is called WAN failover (or policy based routing depending on your needs) and that's of course the job of a router.

ISP's gateways plugged into the same unmanaged network switch.

This will not work and will cause issues with your networks performance

This is something a router would do, not a switch. You would need to have a router with multiple WAN ports so not most consumer routers

Sounds like you need a dual WAN router, and you'll need to set your current two ISP modems so they are not assigning IP addresses. There are some consumer dual WAN routers you can get, I think Asus has some models. You can set them to use one ISP as the primary, and when that drops out, the router automatically uses the secondary. When the primary is back online, the router automatically changes back. You'll get perhaps a few seconds of dropout but it shouldn't need any user intervention.

Get a used SRX300 off eBay.

There's nothing an SRX can't do.

This a good explanation on how to proceed.

https://packetpassers.com/multiple-isp-connectivity-redundancy/

This how to set it up

https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA10g000000ClElCAK

These are firewalls to buy. Fort iNet looks like the best to use for dual isps because it offers load balancing to get the best signal and quick switchover.

These are the ones to buy/choose.

https://www.allconnect.com/blog/the-4-best-hardware-firewalls-for-home-wi-fi

something like TP-Link ER605 router, allows 2 wan links

Use a multi WAN firewall and plug all three ISP into it. You can build one yourself using opnsense or similar.

Not by a switch. You'd need a multi-WAN port router. Something like the ER605 will do failover.

We use an Edgerouter-X for this.

You can achieve this easily with a managed L3 switch, or 2 managed routers. Look up first hop redundancy protocols, specifically vrrp if you want to go with a non cisco managed switch. The switch must support vrf if implementing this solution - basically you need both isp routers to provide the network in the same subnet, on different ports on the switch. The 2 ports on the same switch will be segmented by vrf, and loop across from one vrf to the other. Set up vrrp between the 2 vrf and set up tracking reachability on the primary vrf. You can tweak timers if you want too, but I’d leave them at a few seconds at least for the track to go down and implement a vrrp decrement. Point the default gateway on lan to the vrrp vip address for automatic failover and back for the minimal interruptions. Just bear in mind that these are enterprise grade switches and solutions so cost might be prohibitive, especially in a lower income country. Also you will need to support these technologies so would be good to know what you’re doing as it’s a complex setup. There are other solutions possible, but then again they would rely on other enterprise grade equipment and technologies that you may or may not have access to, and are also going to be cost prohibitive. For a simpler solution, you could look into a consumer grade dual wan router, but I’m not sure if they exist or are any good. Best of luck

Switch, no, router, yes. I used to run an old Linksys wifi router with DD-WRT firmware on it that had two WAN ports, one wired and one wireless. The wired was to my ISP, and the wireless was to my neighbor's, with his consent, of course. If mine went down, I could easily switch to his.

I use the EdgeRouter Lite. You can configure the 3 ports as you like, I use 2 for WAN and 1 for LAN.

Corporate network routers do this.

Technically you could do this with an old Cisco switch and a shell script though. The script would ping a known address on the internet from your computer. When it becomes unpingable, the script telnets into the switch and shuts the interface for the current isp and no shuts the interface for the other isp. Very hacky, but it's what I would do if I were in your situation and I'd use the old Cisco 3750 I've got laying around.

Go check out the Firewalla line. Supports WAN failover and their UI makes it so a complete moron can set this up.

Ddwrt can do this with switching gateways via a script that pings thru each ISP. I do it this way with the other isp in a house a block away connected via Ubiquiti litebeams.

Do you not have a reliable ISP in the area?

What problems are you having with the current ISPs?

You just need a router / gateway that supports load balancing across 2 WANs.

I know that the UI UDM-SE supports this, dont know about others.

Good video here: https://www.youtube.com/watch?v=QHp0FA9yAKE&t=42s