Hi, Please show also: show interface show route all
So when you have both bgp_v6_a and bgp_v6_b established - you have normal routes. And when you have only bgp_v6_a established - you have that unreachable route only? Your bgp sessions are internal (iBGP), so they may probably have bgp_nex_hop different from the router's address. And also because of recursive resolution they may depend on other routes you have in your bird. On Sat, Apr 10, 2021 at 8:02 PM Dez C <[email protected]> wrote: > > Hi, > > all external routes were unreachable (apart from the local loopback > which was imported via direct protocol). master6 consisted solely of > entries like: > > 2a02:xxxx:d00d::/45 unreachable [bgp_v6_a 19:38:23.222 from > 2a02:xxxx:yyyy:53::a] * (100) [ASxxxxx1i] > > No entries whatsoever from the other bgp session (bgp_v6_b), like in > normal operation: > > 2a02:xxxx:d00d::/45 unicast [bgp_v6_a 2021-04-07] * (100) [ASxxxxx1i] > via 2a02:xxxx:yyyy:53::a on eth2 > unicast [bgp_v6_b 2021-04-07] (100) [ASxxxxx1i] > via 2a02:xxxx:yyyy:53::b on eth2 > > > > regards, > Yannis > > > On 4/9/21 11:22 PM, Alexander Zubkov wrote: > > Hi, > > > > And what do you see in your bird's console? "show route" etc. > > > > On Fri, Apr 9, 2021 at 7:10 PM Dez C <[email protected]> wrote: > >> Hello, > >> > >> First message here, although a long-time bird user (not an expert in any > >> way). We're using bird as a bgp speaker for all our VMs that either need > >> to announce routes or import routes from VRFs etc. > >> > >> The setup is pretty straight forward I'd guess. The VM has 2 IPv6 BGP > >> sessions with 2 L3 switches (one per switch). The VM announces one /128 > >> route and imports all routes learned from the BGP sessions. The same > >> routes are learned from both sessions, so whenever I do a 'ip -6 r' I > >> see 2 entries for each route (with different next hops) like: > >> 2a02:xxxx:d00d::/45 via 2a02:xxxx:yyyy:zz::a dev eth2 proto bird metric > >> 32 pref medium > >> 2a02:xxxx:d00d::/45 via 2a02:xxxx:yyyy:zz::b dev eth2 proto bird metric > >> 32 pref medium > >> > >> At some point, both BGP sessions went down and one of them did not > >> recover for an hour. Normally, this should not be a problem but in this > >> specific case, I could no longer see 2 routes in the kernel table, one > >> reachable and another unreachable, just an unreachable one, so even > >> though the anycast route was being announced and traffic was reaching > >> the VM, it couldn't send the packets to their destination as all routes > >> were unreachable in the kernel table: > >> unreachable 2a02:xxxx:d00d::/45 dev lo proto bird metric 32 error -113 > >> pref medium . > >> > >> I'm running 2.0.7 (upgrading soon) on centos7 and here's the relevant > >> part of my config: > >> > >> protocol device { > >> } > >> protocol direct direct_v6_lo { > >> interface "lo*"; # announce loopback > >> ipv6; > >> } > >> protocol direct direct_v6_eth { > >> interface "eth*"; > >> ipv6; > >> } > >> protocol bgp bgp_v6_a { > >> local 2a02:xxxx:yyyy:53::37 as 66666 > >> neighbor 2a02:xxxx:yyyy:53::a as 66666; # switch A > >> ipv6 { > >> export where proto = "direct_v6_lo"; > >> }; > >> } > >> protocol bgp bgp_v6_b { > >> local 2a02:1388:4000:53::37 as 66666; > >> neighbor 2a02:1388:4000:53::b as 66666; # switch B > >> ipv6 { > >> export where proto = "direct_v6_lo"; > >> }; > >> } > >> protocol kernel { > >> ipv6 { > >> export filter { > >> if proto = "direct_v6_eth" then reject; > >> accept; > >> }; > >> }; > >> merge paths limit 2; > >> } > >> > >> any ideas? > >> thanks in advance and regards, > >> Yannis >
