Best practices for redundant iBGP/eBGP route distribution? [bird 2.0.7]

[Nico Schottelius]

Ondrej Zajicek <santiago at crfreenet.org> writes:

> On Mon, Dec 16, 2019 at 01:43:09AM +0100, Nico Schottelius wrote:
>>
>> Follow up 2:
>>
>> it seems that bird1.6 behaves differently to bird 2.0.7:
>>
>> bird> show route all for 2a0a:e5c1:111:111:6aa6:5bc:535a:8e21
>> 2a0a:e5c1:100::/40 via 2a0a:e5c0:1:8::6 on bond0.8 [router2_place6_ungleich_ch_v6 2019-12-03] * (100) [i]
>>         Type: BGP unicast univ
>>         BGP.origin: IGP
>>         BGP.as_path:
>>         BGP.next_hop: 2a0a:e5c0:2:2:0:84ff:fe41:f24d
>>         BGP.local_pref: 500
>> bird>
>>
>> (this is from the 2nd router pair, still running bird 1.6)
>>
>> Is it possible that the nexthop resolution algorithm changed in bird2 vs
>> bird1?
>
> Yes, in BIRD 1 direct mode, there was a fallback that uses IP address
> of BGP peer as gateway if BGP NEXT_HOP failed to resolve.
>
> We removed this fallback in BIRD 2.

Ha, that explains a lot! I am still puzzled though, because the
description of bird2 on the topic of gateway direct seems to imply that
this is still the case.

Is there any way to restore the 1.6 behaviour?

Best,

Nico


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