IPv6 Method "Automatic, DHCP only" breaks ipv6 routing.
Talking about this dialogue (not my screenshot): https://i.imgur.com/qpbL65v.png
Steps to reproduce:
- Open GNOME Settings
- Change IPv6 method to "Automatic, DHCP only"
- IPv6 connectivity lost
The issue is that "Automatic, DHCP only" seems to completely ignore any Router Advertisements on the link. This means the default router is never discovered.
DHCPv6 does not provide any routing information.
I would expect "Automatic, DHCP only" to ignore any prefixes in Router Advertisements and use DHCPv6 to acquire address but the router still added to routing information.
This can also be an issue with NetworkManager.