On Mon, Dec 16, 2019 at 03:40:18PM +0100, Nico Schottelius wrote: > > Ondrej Zajicek <[email protected]> writes: > > > On Mon, Dec 16, 2019 at 01:43:09AM +0100, Nico Schottelius wrote: > >> > >> Follow up 2: > >> > >> it seems that bird1.6 behaves differently to bird 2.0.7: > >> > >> bird> show route all for 2a0a:e5c1:111:111:6aa6:5bc:535a:8e21 > >> 2a0a:e5c1:100::/40 via 2a0a:e5c0:1:8::6 on bond0.8 > >> [router2_place6_ungleich_ch_v6 2019-12-03] * (100) [i] > >> Type: BGP unicast univ > >> BGP.origin: IGP > >> BGP.as_path: > >> BGP.next_hop: 2a0a:e5c0:2:2:0:84ff:fe41:f24d > >> BGP.local_pref: 500 > >> bird> > >> > >> (this is from the 2nd router pair, still running bird 1.6) > >> > >> Is it possible that the nexthop resolution algorithm changed in bird2 vs > >> bird1? > > > > Yes, in BIRD 1 direct mode, there was a fallback that uses IP address > > of BGP peer as gateway if BGP NEXT_HOP failed to resolve. > > > > We removed this fallback in BIRD 2. > > Ha, that explains a lot! I am still puzzled though, because the > description of bird2 on the topic of gateway direct seems to imply that > this is still the case.
That is mistake in docs. > Is there any way to restore the 1.6 behaviour? No, it just hides misconfigurations. If you use 'next hop self' then there should not be difference between BGP NEXT_HOP and peer IP address and it would work even in cases where both IPv4 and IPv6 routes are propagated over one BGP session. -- 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."
