Multiple WAN connections with the same subnet

Hi guys.

I just have approval from my neighbors to have some cables connecting to their routers, so I can get some backup WAN connections. Some of them share me their home Wi-Fi password, so I can have my OpenWrt main router as their wireless client.

Here come the problem: all of them use the subnet I cannot have a route to via multiple intefaces. :joy:

Asking the permission to interfere with their routers are out of the question. Furthermore, local ISPs are quite annoying -- they require the clients to register with them to make the configurations on the ONT permanent, else one reboot is all it takes for everything to go back to again. Changing each ONT configurations is too complicated for me to handle.

Are there any tricks or hack to make all these interfaces work?

You cannot have multiple networks with the same subnet. Period. It will break routing.

Your options are to:

  1. ensure that all of the networks are different (i.e. convince them to change the subnets they use on their networks)
    -- or --
  2. you could insert an intermediary router between your neighbors' routers and yours with another NAT layer. This way, when it comes to your main router with mwan3 installed, it would appear that each network is on a different subnet.
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Looks like a MWAN related topic, but what makes you think it cannot work?
There's no technical limitation using different metrics or custom routing tables.