> Как мне побороть эту проблему?
> В какую сторону копать?
> Спасибо начать с изучения основ ipv6 и чтения RFC, да v6 срань работает местами совсем не так как v4
https://datatracker.ietf.org/doc/html/rfc4861#section-8
A router MUST be able to determine the link-local address for each of
its neighboring routers in order to ensure that the target address in
a Redirect message identifies the neighbor router by its link-local
address. For static routing, this requirement implies that the next-
hop router's address should be specified using the link-local address
of the router. For dynamic routing, this requirement implies that
all IPv6 routing protocols must somehow exchange the link-local
addresses of neighboring routers.