On Tue, Sep 19, 2017 at 10:32:34PM +0200, Alexander Demenshin wrote: > Hi, > > Any reason why 240.0.0.0/4+ routes are ignored by bird (1.6.3)?
Hi I do not know why it was implemented in BIRD originally in such way and i had to need to question that, so it stayed is it was. If Linux and BSD kernels does accept such routes, than it is a strong reason to support that in BIRD, even if only for purpose of defining blackhole static route. While i agree that hardcoding administrative assignments is a bad idea, i would see a case for special handling of 240.0.0.0/4 in contrast to other 'special' ranges. While other ranges were later administratively reassigned from regular uncast forwarding range, 240.0.0.0/4 was reserved for future since deep past, and therefore it is possible that it could be handled in some completely different way in the future (like 224.0.0.0/4 is handled by FIBs differently than unicast). If you just handle it like regular unicast and it is later defined as something completely different, you cannot implement that without breaking backward compatibility. So it seems strange to me that FIBs like Linux kernel does handle it regularly (never tried that), but perhaps they expect that now it will never be reassigned. -- Elen sila lumenn' omentielvo Ondrej 'Santiago' Zajicek (email: [email protected]) OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net) "To err is human -- to blame it on a computer is even more so."
