How to temporarily block the router?

Question

Programming

Connoisseurs, please help. There is a router to which the Internet comes and then the router routes the Internet to the local machine.
Task: to paralyze all connections of the router through the local machine except the local machine. Moreover, it is desirable to do this with a keyboard shortcut. Ie, I pressed the buttons - the Internet does not go to the router, the router itself does not transmit information anywhere except for the LAN. Clicked again - everything works as before.
Could you tell me how to implement such a mechanism? What is required for this?

Answer 1

The bike itself:
Write a batch file that will change the default gateway to the left one and a batch file that will return the desired one.
Hang them on hotkeys, or make one that will trigger.
At the same time, everything will work for you locally, since there is only one subnet, and beyond its limits your computer will not know where to go, so it will not try to go through the router.

Answer 2

• Make a script in a scripting language that accesses it via telnet or ssh (available in almost all routers) and lowers the WAN\PPP interface or removes the 0.0.0.0\0 route from the route table.
  
• Make a shortcut to the script.
  
• Assign a hotkey to a shortcut.