How to raise a mobile proxy on a router via home Internet?

Question

linux

There is a Xiaomi Mi router with "Padavan" firmware - ASUS remake (with a terminal). The router has two internet, cable and usb whistle. When the cable is disconnected, the whistle is connected. As I understand it, they cannot work in parallel.

The task is to use the USB whistle as a proxy remotely and at the same time freely use home / cable Internet.

DDNS (no-ip) is configured on the router, it keeps the connection with the home Internet, it does not work with mobile DDNS because the mobile provider gives gray addresses.

Tell me which way to look. I thought to set up a proxy squid server with mobile Internet on the router, connect to it via DDNS + port (via no-ip home Internet to the router - the router accepts the request and transfers it to the mobile one), is it possible at all? Sorry - I'm new to this.

Answer 1

The router has two internets,

The Internet is a global network. He is one, there cannot be two.

As I understand it, they cannot work in parallel.

Misunderstood, they can work in parallel.

Task to use usb whistle as proxy removed

It's not a question - you take a white address from the provider, raise a proxy on your computer, and that's it.
True, a white address from mobile providers will cost a pretty penny, and there is no quality of wireless communication. So it makes no sense, but it's easy to do.

the router accepts the request and transfers it to the mobile), is it even possible?

Perhaps, if the router can do this. Any normal one can.

Answer 2

I do not know all the features of the task, but perhaps such a scheme will suit you.
Raise two SSIDs on the router, release devices connected by SSID1 to the Internet via wired Internet, SSID2 via mobile Internet.