On Sat, Oct 29, 2022 at 10:29:25PM +0000, Andy Smith via Bird-users wrote: > Hi, > > On BIRD 2.0.7 I've got some eBGP sessions with this config: > > ... > The session establishes and 2001:db8::64:607b sends me some 591 IPv6 > prefixes, however only 385 of them end up in my routing table, > without any logging as to why. > > I've done "debug uplinka6 all" and then "restart uplinka6" and there > is no mention in the logs at all of any of the missing prefixes yet > I can see them in a tcpdump so I know 2001:db8::64:607b is sending. > Also the operator of 2001:db::64:607b is convinced they are being > advertised correctly. > > Watching "ip monitor route" I also see no mention at all of the > prefixes I'm not getting. > > Is there any kind of enhanced debugging I can do to work out why > BIRD does not do anything with some of those prefixes?
Hi Debugging is fixed in v2.0.9, now it logs a detailed reason and all rejected prefixes. > All of those have nexthop 2001:db8::64:608a that being another of my > servers, so to experiment I tried adding a route like BIRD would: > > # ip route add 2001:db8:1f1:c00::/56 via 2001:db8::64:608a metric 500 > > and did get: > > RTNETLINK answers: No route to host > > which is odd because there is a route that was accepted for this > nexthop: > > $ ip route get 2001:baf::64:608a > 2001:db8::64:608a from :: via 2001:db8::64:607b dev bond0 proto bird src > 2001:db8:0:1f1::e metric 500 pref medium If 2001:db8::64:608a is not directly reachable, but reachable through another route, then you need recursive next hop resolution. That is enabled by default just for IBGP / multihop sessions, as it is usually not needed for EBGP / direct sessions. See: https://bird.network.cz/?get_doc&v=20&f=bird-6.html#bgp-gateway Try: protocol bgp uplinka6 { local 2001:db8::64:607a as 64607; neighbor 2001:db8::64:607b as 64943; hold time 30; ttl security on; ipv6 { import all; export filter bgp6_out; gateway recursive; }; } -- 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."
