[BFD] BFD is Not working after system reboot.

[Kees Meijs | Nefos]

Hi Seunghwan,

It might be your problem isn't BIRD but packet filter related.

Please check the BFD packets are allowed in iptables c.q. netfilter
using the correct ports and/or addresses.

A possible reason why it starts working after a manual protocol restart
is a ESTABLISHED, RELATED rule.

References:

  * https://tools.ietf.org/html/rfc5881 (Encapsulation, IANA Considerations)
  * https://tools.ietf.org/html/rfc5883 (IANA Considerations)


K.

On 16-07-2020 11:00, seunghwan hwang wrote:
> Hello.
> BFD is Not working normally.
> My configuration is shown below.
>
> OS: Ubuntu 18.04
> Kernel: 4.15.0-54-generic
> BIRD ver: 1.6.8
> ==================================
> protocol bfd {
>         multihop {
>             min rx interval 300 ms;
>             min tx interval 300 ms;
>             multiplier 3;
>         };
> }
>
> protocol bgp as1 {
>         import all;
>         export all;
>
>         local ~ as ~;
>         neighbor ~  as ~;  
>         enable route refresh off;
>         hold time 90;
>         bfd on;
> }
>
> protocol bgp as2 {
>         import all;
>         export all;
>
>         local ~ as ~;
>         neighbor ~  as ~;  
>         enable route refresh off;
>         hold time 90;
>         bfd on;  
> }
> ==================================  
>
> After system reboot(# shutdown -r now), BGP neighbor is established,
> But BFD sessions are stuck in 'INIT' status. And BIRD does not send
> BFD packets.
> BFD sessions have recovered after restart protocol bfd1(# birdc
> restart bfd1).
>
> Is it a normal situation?
> I think BFD has to start the mechanism after BGP neighbor is UP.
> Is there any missing part of my configurations?
> Please check it.
>
> Regards

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