Subject: Bird3 - Establishing a BGP session over IPv6 LL addresses

[Alexander Zubkov]

Just for the note. "direct" and "device" - are different protocols.

On Thu, Mar 26, 2026 at 11:21 PM Lucas da Vila <dev at ldv.ar> wrote:

> Well, at least over IPv4 it was not necessary to have a "direct" protocol.
>
> But I'll try
>
> Regards,
> Lucas
>
> On Thu, Mar 26, 2026, 18:28 Alexander Zubkov <green at qrator.net> wrote:
>
>> Hi Lucas,
>>
>> "protocol device" might be an issue, I think it's almost must-have for
>> bgp. Because to establish the session bird needs to know interfaces and ip
>> information. And that is supplied by "protocol device".
>> https://bird.nic.cz/doc/bird-3.2.0.html#device
>>
>> Regards,
>> Alexander
>>
>> On Thu, Mar 26, 2026 at 10:10 PM Lucas da Vila <dev at ldv.ar> wrote:
>>
>>> Hi Alexander,
>>>
>>> I don't have a "protocol device" I was just hoping to receive the
>>> announcements from the RR a get the BMP output for analysis.
>>>
>>> Regards
>>> lucas
>>>
>>>
>>> On Thu, Mar 26, 2026, 16:46 Alexander Zubkov <green at qrator.net> wrote:
>>>
>>>> Hi Lucas,
>>>>
>>>> I have some working bgp sessions over link-local addresses. Only that
>>>> they are hand-configured, not automatic ones. And I have bird2, not bird3.
>>>> My config is something like this:
>>>>
>>>> protocol bgp bgp_router_c6 {
>>>>         neighbor fe80::2 as 65000;
>>>>         local fe80::1 as 65000;
>>>>         interface "vlan100";
>>>>         direct;
>>>>         strict bind yes;
>>>>         free bind yes;
>>>>
>>>>         ipv6 {
>>>>                 next hop keep; ...
>>>>         };
>>>> }
>>>>
>>>> "free bind" should not be necessary here, I think. Do you have
>>>> "protocol device" in your config?
>>>>
>>>> Regards,
>>>> Alexander Zubkov
>>>>
>>>> On Thu, Mar 26, 2026 at 8:21 PM Lucas da Vila <dev at ldv.ar> wrote:
>>>>
>>>>> Hi!
>>>>>
>>>>> I'm a member of the DN42 network, and I have a mikrotik router
>>>>> connected to it, I've only have 1 peer and I'm receiving over MP-BGP IPv4
>>>>> and IPv6 prefixes. Also on the mikrotik I'm running a route-reflector.
>>>>>
>>>>> With my bird3 (3.2.0 from debian repo) instance I'm trying to connect
>>>>> to the route reflector over a couple of IPv6 LL addresses. But it doesn't
>>>>> seem to be working. This is my bird3 config:
>>>>>
>>>>> ```
>>>>> router id 192.168.1.200;
>>>>>
>>>>> log "/var/log/bird/bird.log" all;
>>>>>
>>>>> protocol bgp mkt01_dn42_rr {
>>>>>         description "mkt01 dn42 RR";
>>>>>         # local 192.168.1.200 as 64512;
>>>>>         local fe80::42e2:30ff:fe60:edbb%wlp2s0 as 64512;
>>>>>         # neighbor 192.168.1.201 as 64512;
>>>>>         neighbor fe80::2805%wlp2s0 as 64512;
>>>>>
>>>>>         interface "wlp2s0";
>>>>>         direct;
>>>>>         strict bind yes;
>>>>>
>>>>>         ipv4 {
>>>>>                 import all;
>>>>>         };
>>>>>
>>>>>         ipv6 {
>>>>>                 import all;
>>>>>         };
>>>>>
>>>>> }
>>>>>
>>>>> protocol bmp {
>>>>>         station address ip 127.0.0.1 port 5000;
>>>>>         monitoring rib in pre_policy;
>>>>>         monitoring rib in post_policy;
>>>>> }
>>>>> ```
>>>>>
>>>>> After trying adding and removing params liks strict bind, interface,
>>>>> etc I was not able to land a configuration that finally worked.
>>>>>
>>>>> I must say that over IPv4 the session was established, but over IPv6
>>>>> stills in Idle.
>>>>>
>>>>> Is anyone out there with a similar config? Any ideas why this happens?
>>>>>
>>>>> Regards,
>>>>> Lucas
>>>>>
>>>>
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