Hi David, thank you for the clarification. Regarding the commercial feature request — this is something we could definitely consider and potentially agree on from our side. In the meantime, I experimented a bit and, with the help of AI, prepared and tested a patch that allows setting the BGP aggregator attribute directly in filters. It works for our use case so far, so perhaps it could be useful for others as well. Best regards, Pavel Dne 14. 04. 26 v 16:00 David Petera via Bird-users napsal(a):

Hi Pavel,

sadly, BIRD does not currently support setting the BGP aggregator attribute. (You can only unset it in the filters using `unset` function)

Neither is there a plan to add support for it in the near future.

However we offer commercial feature request contracts, in case your organization would be able to provide funds for such development. You can find more info about it on our website: https://bird.nic.cz/commercial-services/#deployments-feature-request

Hope this helps, David

David Petera (he/him) | BIRD Tech Support | CZ.NIC, z.s.p.o. On 4/14/26 14:31, Pavel Trefný wrote:

...

Hi,

I have a question regarding BIRD. Is it possible to set the BGP aggregator attribute for a prefix using filters?

This would be useful in our anycast setup, where it can be difficult to determine the origin of a prefix. Using communities is unfortunately not a viable option for us — some of our hardware does not support extended communities, and upstream networks often filter them.

To clarify, I am not looking for route aggregation itself, but specifically a way to set the aggregator attribute.

Thank you for any insights.

Best regards, Pavel Trefny