Route matching filter not exported

Alexander Zubkov green at qrator.net
Fri May 17 16:49:30 CEST 2024


Hello,

Just curious. You've done "reload out" to your session after changing
the filter, right?

Regards,
Alexander

On Fri, May 17, 2024 at 4:45 PM Nico Schottelius via Bird-users
<bird-users at network.cz> wrote:
>
>
> Hello bird users,
>
> I've a strange case in which a router does not export routes that are
> matched by the export filter. I am using the filter "static_and_bgp"
> inside our iBGP sessions:
>
> --------------------------------------------------------------------------------
> bird> show protocol all   ibgp_server137
> Name       Proto      Table      State  Since         Info
> ibgp_server137 BGP        ---        up     2024-05-12    Established
>   BGP state:          Established
>     Neighbor address: 2a0a:e5c0:0:b::89
>     Neighbor AS:      199553
>     Local AS:         199553
>     Neighbor ID:      91.194.139.7
>     Local capabilities
>       Multiprotocol
>         AF announced: ipv4 ipv6
>       Route refresh
>       Extended next hop
>         IPv6 nexthop: ipv4
>       Graceful restart
>       4-octet AS numbers
>       Enhanced refresh
>       Long-lived graceful restart
>     Neighbor capabilities
>       Multiprotocol
>         AF announced: ipv4 ipv6
>       Route refresh
>       Extended next hop
>         IPv6 nexthop: ipv4
>       Graceful restart
>       4-octet AS numbers
>       Enhanced refresh
>       Long-lived graceful restart
>     Session:          internal AS4
>     Source address:   2a0a:e5c0:0:b::91
>     Hold timer:       197.601/240
>     Keepalive timer:  4.476/80
>   Channel ipv6
>     State:          UP
>     Table:          master6
>     Preference:     100
>     Input filter:   ACCEPT
>     Output filter:  static_and_bgp
>     Routes:         204647 imported, 2 exported, 204647 preferred
>     Route change stats:     received   rejected   filtered    ignored   accepted
>       Import updates:        6285634          0          0       3097    6282537
>       Import withdraws:      3559063          0        ---        189    3558874
>       Export updates:        6768067    6387362      37995        ---     342710
>       Export withdraws:      3370586        ---        ---        ---     334365
>     BGP Next hop:   2a0a:e5c0:0:b::91 fe80::2f0:cbff:fefe:b70c
>     IGP IPv6 table: master6
>   Channel ipv4
>     State:          UP
>     Table:          master4
>     Preference:     100
>     Input filter:   ACCEPT
>     Output filter:  static_and_bgp
>     Routes:         947321 imported, 3 exported, 947318 preferred
>     Route change stats:     received   rejected   filtered    ignored   accepted
>       Import updates:       22332349          0          0       2202   22330147
>       Import withdraws:     15475598          0        ---        343   15475255
>       Export updates:       24213451   22602108          0        ---    1611343
>       Export withdraws:     14527850        ---        ---        ---    1598351
>     BGP Next hop:   2a0a:e5c0:0:b::91 fe80::2f0:cbff:fefe:b70c
>     IGP IPv4 table: master4
>     IGP IPv6 table: master6
> --------------------------------------------------------------------------------
>
> As you can see, the router in question only exports 2 IPv6 routes and 3
> IPv4 routes and uses the filter "static_and_bgp".
>
> When I check the route count matching the filter, the numbers look very
> different:
>
> --------------------------------------------------------------------------------
> bird> show route filter static_and_bgp count
> 2841971 of 2841971 routes for 947325 networks in table master4
> 613945 of 613983 routes for 204686 networks in table master6
> Total: 3455916 of 3455954 routes for 1152011 networks in 2 tables
> bird>
> --------------------------------------------------------------------------------
>
> And looking at some routes in detail:
>
> --------------------------------------------------------------------------------
> bird> show route filter static_and_bgp
> Table master4:
> 0.0.0.0/0            unicast [ibgp_server137 11:03:59.224 from 2a0a:e5c0:0:b::89] * (100/?) [AS209898i]
>         via fe80::3eec:efff:fed2:d1e4 on eth0
>                      unicast [outgoing_server120 08:53:28.568] (100) [AS209898i]
>         via 2a0a:e5c0:31:4::1 on tun1
>                      unicast [outgoing_server121 08:55:44.577] (100) [AS209898i]
>         via 2a0a:e5c0:32:4::1 on tun0
> 49.14.107.0/24       unicast [ibgp_server137 11:03:59.224 from 2a0a:e5c0:0:b::89] * (100/?) [AS45271i]
>         via fe80::3eec:efff:fed2:d1e4 on eth0
>                      unicast [outgoing_server120 08:55:43.482] (100) [AS45271i]
>         via 2a0a:e5c0:31:4::1 on tun1
>                      unicast [outgoing_server121 08:55:44.577] (100) [AS45271i]
>         via 2a0a:e5c0:32:4::1 on tun0
> 181.123.200.0/22     unicast [ibgp_server137 11:03:59.224 from 2a0a:e5c0:0:b::89] * (100/?) [AS23201i]
>         via fe80::3eec:efff:fed2:d1e4 on eth0
>                      unicast [outgoing_server120 08:55:30.698] (100) [AS23201i]
>         via 2a0a:e5c0:31:4::1 on tun1
>                      unicast [outgoing_server121 08:55:44.577] (100) [AS23201i]
>         via 2a0a:e5c0:32:4::1 on tun0
> 88.218.186.0/24      unicast [ibgp_server137 11:03:59.224 from 2a0a:e5c0:0:b::89] * (100/?) [AS62240i]
>         via fe80::3eec:efff:fed2:d1e4 on eth0
>                      unicast [outgoing_server120 08:55:22.108] (100) [AS62240i]
>         via 2a0a:e5c0:31:4::1 on tun1
>                      unicast [outgoing_server121 08:55:44.577] (100) [AS62240i]
>         via 2a0a:e5c0:32:4::1 on tun0
> --------------------------------------------------------------------------------
>
> I verified that 2a0a:e5c0:31:4::1 and 2a0a:e5c0:32:4::1 are resolvable
> via OSPF on the other routers:
>
> --------------------------------------------------------------------------------
> bird> show route for 2a0a:e5c0:32:4::1
> Table master6:
> 2a0a:e5c0:32:4::/64  unicast [ospf6 2024-05-12] * I (150/20) [91.194.139.99]
>         via fe80::2f0:cbff:fefe:b70c on eth2
>                      unicast [outgoing_server120 11:11:16.933] (100) [AS209898i]
>         via 2a0a:e5c0:31:2::1 on oserver120
> bird>
> --------------------------------------------------------------------------------
>
> But this should not matter at this stage, because the originating router
> does not seem to try to send this route.
>
> What am I missing, why is a route matching the same filter not being
> exported?
>
> Best regards,
>
> Nico
>
> --
> Sustainable and modern Infrastructures by ungleich.ch



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