"<ERR> bfd1: Socket error: Destination address required"

[Fran]

Hello there,

I get the error message:

"<ERR> bfd1: Socket error: Destination address required"

(ubuntu 22.04, bird via ppa 2.15.1) running BFD and MP-BGP via IPv6 over 
wireguard interfaces. Not all BGP neighbors are reachable.

Relevant (I hope) config:

log "/var/log/bird/bird.log" all;

protocol device {
}

protocol bfd {
   accept ipv6 direct;
   interface "wg_blue*";
   interface "wg_green" {
     multiplier 3;
     interval 500 ms;
   };
   neighbor 2001:db8:f000::2 dev "wg_green" local 2001:db8:f000::1;
   neighbor 2001:db8:f000:ffff::2 dev "wg_blue2" local 
2001:db8:f000:ffff::1;
   neighbor 2001:db8:f000:fffc::5 dev "wg_blue1" local 
2001:db8:f000:fffc::1;
   neighbor 2001:db8:f000:fffc::4 dev "wg_blue1" local 
2001:db8:f000:fffc::1;
   neighbor 2001:db8:f000:fffc::3 dev "wg_blue1" local 
2001:db8:f000:fffc::1;
   neighbor 2001:db8:f000:fffc::2 dev "wg_blue1" local 
2001:db8:f000:fffc::1;
}


protocol bgp EXAMPLE {
   local as 65001;
   neighbor 2001:db8:f000::2 as 65044;
   direct;
   med metric yes;
   ipv4 {
     ...
   };
   ipv6 {
     ...
   };
   bfd on;
}


If I remove the BFD config for the non-established BGP neighbors, the 
error message disappears (although there are still non-established BFD 
sessions for established BGP neighbors (BFD not yet confed on the other 
end)).

At first I did not create neighbor statements for BFD, then I added 
"dev" and "local" options - no improvement.

No revelations with "debug protocols all".

Any ideas? Thanks a lot!

Best,

fran