(Re)export unreachable routes via BGP.

[Grant Taylor]

Is it possible to (re)export unreachable routes via BGP?







Thank you in advance for any help / enlightenment that you can provide.

--8<--
bird> show protocols all grant
name     proto    table    state  since       info
grant    BGP      bogons   up     21:12       Established
  Description:    Feed to Grant at home
  Preference:     100
  Input filter:   REJECT
  Output filter:  ACCEPT
  Routes:         0 imported, 0 exported, 0 preferred

-->8--

--8<--
filter cymru_bogons_import {
   bgp_community.add((REDACTED,888));
   #dest = RTD_BLACKHOLE;
   accept;
}

filter cymru_bogons_export {
   reject;
}

protocol bgp cymru1 {
   description "Team Cymru Bogons Route Server #1";
   import filter cymru_bogons_import;
   #export filter cymru_bogons_export;
   #import all;
   export none;
   multihop 255;
   local as REDACTED;
   neighbor REDACTED as REDACTED;
   source address REDACTED;
   table bogons;
}

protocol bgp cymru2 {
   description "Team Cymru Bogons Route Server #2";
   import filter cymru_bogons_import;
   #export filter cymru_bogons_export;
   #import all;
   export none;
   multihop 255;
   #password "FIXME";
   local as REDACTED;
   neighbor REDACTED as REDACTED;
   source address REDACTED;
   table bogons;
}

protocol bgp grant {
   description "Feed to Grant at home";
   import none;
   export all;
   multihop 255;
   local as REDACTED;
   neighbor REDACTED as REDACTED;
   source address REDACTED;
   table bogons;
}
-->8--



--
Grant. . . .
unix || die

I have established a pair of BGP neighbor sessions with Team Cymru Route Servers, both of which are receiving unreachable prefixes, namely bogons, like they should be. I would like to (re)export said prefixes to a different machine that is not able to form a BGP neighbor session with Team Cymru (for various reasons). All attempts thus far have resulted in the BGP neighbor session with the 3rd test machine not (re)exporting any unreachable routes. I can (re)export other routes without a problem. It looks to me like BGP is rejecting the the routes (I think) because they are unreachable. "show route table bogons" works as expected, and shows the routes received via both of the BGP neighbor sessions with the Team Cymru Route Servers. Similarly, I can see the unreachable routes in the proper table from Linux. Route change stats: received rejected filtered ignored accepted Import updates: 0 0 0 0 0 Import withdraws: 0 0 --- 0 0 Export updates: 3031 3031 0 --- 0 Export withdraws: 0 --- --- --- 0

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