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MikroTik App
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Mutually exclusive dual WAN

Wed Feb 03, 2021 3:00 am

My office has an "unreliable" ISP, that sometimes goes down for a day or more at a time. I have no better ISP choices, so I have to live with it.

My plan was to get a 'travel router' to connected a 4G wireless hotspot to the Mikrotik, thinking I would literally swap the WAN cable from the ISPs modem to the travel router. Unfortunately, the travel router limits the supported IP/Subnets to 192.168, 172., and 10.0. subnets, which don't overlap the static IP that my ISP provides. Maybe I picked the wrong travel router?

That means I have to create a second WAN on the Mikrotik or reconfigure the WAN each time the switch happens. It looks like "fallover" is pretty complex for a old soul to understand, let alone implement. Most of the videos I've found are in Slovakian(?) or in such a heavy accent that they are very difficult to follow. This is my wife's small office, and I'm a long retired hardware engineer that works on an as needed volunteer basis. I want my wife to be able to accomplish the switchover by just turning on her hotspot, since I'm generally not in the office.

I'm hoping that the fact that since I don't really want load balancing, rather just a backup path that only needs to fallover one direction, it might be simpler than typical scenarios?

I've used WebFig for everything I've done up to now, which is to do basic setup and create VPN/L2TP remote access. It's been working fine for months except for this ISP problem. The VPN access can fail when I'm in emergency mode.

One other thing is that the "production" ISP is about 1/4 the speed of the 4G connection, if that complicates things. It's SO FRUSTRATING to see two fiber optic cable vendors hanging on the pole outside the office, and not be able to get fiber...
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Re: Mutually exclusive dual WAN

Mon Feb 08, 2021 8:11 am

I used this to setup dual wan failover. In testing it, it seems to work very fast. They did misspell masquerade in the commands, so you can't just copy and paste it.
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Re: Mutually exclusive dual WAN

Tue Feb 09, 2021 6:37 pm

You could leave your "travel" router on its default subnet, connect one of its LAN ports to an interface on your Mikrotik. On the MT interface enable DHCP client and add it to WAN interface group so that your traffic will be NATed. Now your travel router doesn't need to know about your own subnets. Next, configure a second default route on the Mikrotik via the travel router i/f. If your main connection is prone to going down altogether you could configure automatic failover.

Simple manual failover would be just two default routes, lower preference for the main ISP connection, and use Winbox or Webfig to disable that route when you want to go via 4G.

Let us know if you need more detail on any of this.

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