Enable IPv6 on LAN, assign Link-Local addresses ONLY

I got a ipv6 to ipv4 tunnel working and am able to assign ipv6 addresses to my lan hosts; but there's a problem: devices start to prefer ipv6 now, and Netflix stopped working for my family because they detect that I'm going through a tunnel. so my question is:

how can I configure the ipv6 DHCP/RA to only hand out link local addresses to my lan, so they can never get outside using ipv6?

or, alternatively, how to work around the Netflix / ipv6 tunnel issue and force ipv4 when connecting to Netflix?

Turn off IPv6 advertising on the interfaces.

Link-local, IPv6 addresses will self-assign.


If possible (based on your cabling/ wireless situation), I would suggest to put just the netflix using devices into a dedicated non-IPv6 enabled subnet, while keeping it for the normal ones (IPv6 capability is increasingly becoming important).