On Mon, May 11, 2026 at 12:48:48PM +0100, Lexi Winter wrote: > Ondrej Zajicek wrote in <agG8FCXbKhBjqsvg@feanor>: > > On Sun, May 10, 2026 at 01:42:07PM +0100, Lexi Winter wrote: > > > i have an interface with a /64 address configured: > > >[...] > > > however, BIRD only adds a /128 route into the OSPF database > > > > There are two reasons why it could generate /128 route instead of /64. > > Either BIRD thinks there is link down in the interface, or it is > > confused by its type and handles the interface as PtMP. > > thanks. setting 'check link no' fixed the problem, but i'm not sure > i understand why. > > on the host, the interface is up: > > bridge0.500: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric > 0 mtu 1500 > > but BIRD considers it down (LinkDown): > > bridge0.500 up (index=28) > MultiAccess Broadcast Multicast AdminUp LinkDown MTU=1500 > fe80::1/64 (Preferred, scope link) > fd13:480d:2ffa:3::1/64 (Preferred, scope site) > > looking at another interface that BIRD considers LinkUp: > > bridge0 up (index=27) > MultiAccess Broadcast Multicast AdminUp LinkUp MTU=9000 > > i see it has the LOWER_UP flag in ifconfig: > > bridge0: flags=1008843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST,LOWER_UP> > metric 0 mtu 9000 > > so, it seems like the problem is that the host system isn't setting this > flag on the vlan interface, even though it probably should be set since > the underlying interface is up. > > does that seem like a reasonable explanation for this behaviour? if so, > i will go away and see if we can fix the host :-)
Yes, that looks like the right explanation. Not sure if it is a missing implementation in kernel or a bad assumption on BIRD part. -- Elen sila lumenn' omentielvo Ondrej 'Santiago' Zajicek (email: [email protected]) "To err is human -- to blame it on a computer is even more so."
