¡Hola!

On Fri, Nov 21, 2025 at 01:37:57PM +0100, Maximilian Wilhelm via Bird-users wrote:

• 2. filter output vs. export reality Independent of whether we filter on “all best” or “all routes”, in the CLI the filter output shown does include the route - if the filter does not match, it also should not print it

Well, if you do show route filter xyz, then you get all routes matching that filter. Some protocols pick them. You can do show route export bgp_to_internet.ipv6 to explicitly re-run the export filter in that context.

I know that it is kinda confusing, and we should probably improve our documentation to show this properly.

A show route primary filter xyz should also be equivalent to what’s actually exported, right?

Almost! It is, in that case, equivalent to what should be exported if there was no preexport limitation. The most prominent case is back-export to Pipe and BGP; these two protocols reject their own routes, while others (e.g. Babel) accept them.

With that, you need this:

show route primary filter xyz preexport bgp_to_internet.ipv6

Starting with BIRD 3, some routes might be also export-pending because BGP runs in different threads than the CLI. This isn’t reflected in any output for now because that information is performance sensitive and almost impossible to access ad-hoc safely.

We also expect to add protocol contexts, and as soon as this happens, you would need something like

show route primary filter xyz preexport bgp_to_internet.ipv6 context { ... }

to match show route export bgp_to_internet.ipv6 output.

Last but not least, if you change your filters but call configure soft, the affected channels do not reload at all, and therefore to find out which routes were actually exported, you may ask for

show route exported bgp_to_internet.ipv6

but if the export filter did any changes, it’s already lost because the export filter is forgotten with the reconfiguration. Only if you have export table on, then you may ask for

show route export table bgp_to_internet.ipv6

and it actually shows not only what has been exported but also it may tell you what has been exported but not yet sent to the peer. Not only that, in BIRD 3, this call works always, and with export table off, it shows exactly the routes which have not yet been sent into the TCP socket.

And that’s been quite an infodump which may have left you even more confused but now at least it’s dumped.

We should definitely do some major updates to the documentation.

Maria

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Maria Matejka (she/her) | BIRD Team Leader | CZ.NIC, z.s.p.o.