TIL: So #IPv6 Neighbor Advertisement has this R-flag. Guess what happens to macOS when it receives NA massage from a router without this flag on?
How can a router emit NAs without R-flag on? Ehm, ehm, NetworkManager. 🙄
https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/issues/923
IPv6 forwarding should not be forcibly disabled on device setup (#923) · Issues · NetworkManager / NetworkManager · GitLab
ip6_managed_setup(NMDevice *self) in src/core/devices/nm-device.c forcibly disables IPv6 forwarding for the device. This basically invalidates the global IPv6 forwarding setting (net.ipv6.conf.all.forwarding) for devices managed by NetworkManager.GitLab
NetworkManager
in reply to Ondřej Caletka • • •