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

[Lucas da Vila]

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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