> I just though that the default value for the option is enabled, but > perhaps it should be enabled only if such routes are supported by > platform code (i.e. enabled on Linux, but disabled on BSD, as we do > not support such routes on BSD).
IMHO, it should not be possible to enable v4-via-v6 unless the platform supports it. Otherwise, you risk creating persistent blackholes. (There's also the PMTUD problem described in RFC 9229 Section 3.) -- Juliusz
