One Shop, Two ISPs. How to make it work?

[RA2024]

First time poster here. I thank you for your assistance in advance.

My retail shop uses Comcast Cable (calling it CC going forward) as the ISP. I just added Verizon 5G Business internet (calling it VZ going forward) as the backup for the times when CC is down (which has been more often than I like).

The LAN IP for the CC router is 10.1.10.1
The LAN IP for the VZ router is 192.168.0.1

The problem is that every time when a device connects to the VZ network, it will get assigned, by the VZ router, the default gateway of 192.168.0.1 and an IP in the 192.168.0.x range, which is fine, but when I'd connect back to the CC network, somehow the 192.168.0.1 default gateway and the 192.168.0.x IP get stuck in the device. Now, this device cannot be seen in the CC network nor can it go to the internet. I have to manually renew the IP on the device so that it will go back to 10.1.10.1 default gateway and a 10.1.10.x IP.

I am thinking:
I will change the VZ router?s LAN IP to be the same as the CC router's 10.1.10.1
I will then set the VZ router?s DHCP range to be the same range as that in the CC router.
We would NOT connect to the VZ network unless CC is down. This should avoid the conflict of having two routers with the same LAN IP.

Will this solve the problem?

[Midknyte]

Ideally, you would want a dual WAN router. That way, you'd be using the bandwidth of both the ISP, not just having a dormant one. And if one ISP goes down, it wouldn't require switching routers and refreshing the PC's IPs.

One example is that Asus RT-AX3000 aka RT-AX58U (Best Buy model)
https://dongknows.com/asus-rt-ax3000-rt-ax58u-review/

Of course there are business class dual WAN routers also, but those are going to be more expensive.

[Midknyte]

As for what you were thinking:

I will change the VZ router?s LAN IP to be the same as the CC router's 10.1.10.1
I will then set the VZ router?s DHCP range to be the same range as that in the CC router.
We would NOT connect to the VZ network unless CC is down. This should avoid the conflict of having two routers with the same LAN IP.

If the VZ router is only going to be connected if CC goes down, then using the same router IP should work. You cannot have 2 devices on the network with the same IP.

If you use the same DHCP range, there is a chance that 2 devices get assigned the same IP.
Ex. CC assigns 10.1.10.10 to PC1. You switch the routers. Then the VZ router tries to assign 10.1.10.10 to PC2. The VZ router has no way of knowing that 10.1.10.10 is already in use.
If anything, you could try setting CC to 10.1.10.50-99 and VZ to 10.1.10.100-149.

This will still require manual switching and configuring. That's why a dual WAN router would be a much better solution. It would probably pay for itself in the long run, since there would be way less downtime.

[jdc2000]

Another option for a dual-WAN router:

https://www.zdnet.com/article/best-vpn-router/

https://www.zdnet.com/home-and-offic...you-might-too/

https://www.pcmag.com/reviews/synology-router-rt2600ac

https://www.cnet.com/reviews/synology-rt2600ac-review/

https://www.amazon.com/Synology-RT26...01N5MPTG1?th=1

[RA2024]

With a Dual-WAN router, the IP addresses and default gateway ip on the devices will get renewed immediately and automatically when the WAN is switched from one to the other (in a Fail-Over configuration)?

[jdc2000]

The failover settings and configuration may vary depending on the router chosen. You would need to check the specifications of the router(s) that you are interested in to see what settings are available and how the failover works.

[RA2024]

Do I need to configure the CC and VZ gateway in any special way before I plug them in dual-WAN router, or is it plug-&-play?

[Midknyte]

The dual WAN router wouldn't need to change IPs or default gateways on the clients during failover/failback. The only thing that changes is WAN port (primary or secondary).

[Midknyte]

Do I need to configure the CC and VZ gateway in any special way before I plug them in dual-WAN router, or is it plug-&-play?

You would need to disable DHCP on both of them. Basically they just need to be modems, not routers.

Ex. modem 1 >> WAN port 1, modem 2 >> WAN port 2 (or LAN port #X depending on the config)

[RA2024]

I have been reading up on using a dual-WAN router online ever since you guys suggested it. I've heard about setting both gateways from CC and VZ in Bridge mode. My understanding is that the Bridge mode simply turns off WiFi radios and DHCP in the gateway, so that it is acting only as a modem but not a router, so that the dual-WAN router is now the only device handling routing and WiFi. Do I understand this correctly?

[jdc2000]

Possibly useful link:

https://www.howtogeek.com/867942/wha...r-bridge-mode/

[jdc2000]

One other advantage of a dual-WAN router is that there is no manual process involved during a failure of the primary ISP. If you are on the beach at Bora-Bora you do not want a call from the office asking for assistance in switching to the backup ISP while you are in the middle of some surfing lessons.

[Midknyte]

so that the dual-WAN router is now the only device handling routing and WiFi.

Yes.

As jdc2000 mentioned, the dual-WAN router would have automatic failover/failback if you set it up properly. The users may not even be aware if ISP1 goes down.

[RA2024]

Watching YouTube videos om this topic, I notice that, with many TP-Link routers you can enable BOTH "load balancing" AND "failover". But with Asus routers (which is my preferred brand of routers) it is EITHER "load balancing" OR "failover".

I'd rather to have both. But then I read that some people suggest that, by logic, "load balancing" will provide the "failover" functionality because of the way it works. The logic is that, since "load balancing" uses both ISP connections, it would make sense that when ISP A connection is down, all the traffic will simply go through ISP B connection, and, when A is recovered, both will be used again. This sounds logical, but is it true in reality. If that is not true, then, does it mean that in "load balancing" mode, if any one of the ISP connections is out, there will be NO internet at all????

[Midknyte]

If that is not true, then, does it mean that in "load balancing" mode, if any one of the ISP connections is out, there will be NO internet at all????

You'd need to look at the specific hardware, but load balancing usually means it is using both WAN connections simultaneously. If one goes down, the other one would still be up. That's the point.

Failover means it would only use the second connection if the primary connection times out. Failback is when it switches from the secondary back to the primary.