On 2023-04-18 05:34, Per Jessen wrote:
I have no idea which is the IPv6 address of the router or how to find
it. 
Maybe this will do the trick - 

ip -6 neigh | grep router

Otherwise 

ip -6 neigh | grep mac-addr-of-router

Or just fire up Wireshark and see where all the router advertisements are coming from.