Prefix not making it through two iBGP sessions

[Brooks Swinnerton]

I stumbled upon Jobs' response over in
https://bird.network.cz/pipermail/bird-users/2018-July/012572.html and
adding `rr client;` on router 1 resolved the issue.

On Sat, Dec 14, 2019 at 10:18 AM Brooks Swinnerton <bswinnerton at gmail.com>
wrote:

> Hello,
>
> I'm having trouble understanding why certain routes aren't making it
> through to an iBGP session on BIRD 2.0.7.
>
> My network layout looks something like below. I have three BIRD instances
> running, *Router 1* is connected to *Upstream 1*, *Router 2* is connected
> to *Upstream 2*, and *Router 1* and *Router 2* are connected to each
> other via iBGP. This all works great.
>
> Upstream 1         Upstream 2
>     ▲                  ▲
>     |                  |
>    eBGP               eBGP
>     |                  |
>  Router 1 ◀--iBGP--▶ Router 2
>     |
>    iBGP
>     |
>     ▼
>  Router 3
>
> The problem comes with *Router 3* not receiving routes from *Router 2*.
>
> The iBGP export filter on router1 looks like this:
>
>     export filter {
>       if is_v4_bogon() then reject;
>       if is_v4_default() then reject;
>       if is_v4_peering_net() then reject;
>       if is_v4_own_net() then accept;
>       if source = RTS_BGP then accept;
>       reject;
>     };
>
> And if I test each of these functions out manually I can see the prefix
> should be allowed through:
>
> bird> show route filter { if is_v4_bogon() then reject; } 174.202.0.0/16
> bird> show route filter { if is_v4_default() then reject; } 174.202.0.0/16
> bird> show route filter { if is_v4_peering_net() then reject; }
> 174.202.0.0/16
> bird> show route filter { if is_v4_own_net() then accept; } 174.202.0.0/16
> bird> show route filter { if source = RTS_BGP then accept; }
> 174.202.0.0/16
> Table master4:
> 174.202.0.0/16       unicast [cologuard4 21:17:56.850 from 169.254.3.3] *
> (100) [AS22394?]
>         dev bdr-cologuard
>
> Unfortunately if I look at the session from *Router 1* to *Router 3*
> (core_nyiix_14), it is not let through:
>
> bird> show route export core_nyiix_14 174.202.0.0/16
> bird>
>
> I've added all of the relevant configuration in this Gist
> <https://gist.github.com/bswinnerton/6b7527bc9d78215275c1ae75e64d34cd>.
>
> Any help would be much appreciated.
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://trubka.network.cz/pipermail/bird-users/attachments/20191214/1b3a6c7c/attachment.htm>