Hi, That is exactly what "filter" function does. Something like this: bgp_community.filter([(64511,*)]); On Wed, Jul 19, 2023, 17:15 Marek Küthe <m-k-mailling-list@mk16.de> wrote:

Hello,

I recently discovered a new filter for myself on https://bgpfilterguide.nlnog.net/guides/many_communities/#bird. In my eyes it also makes sense to keep the routing table as small as possible. But now I don't want to delete all communities, but keep a single one. How can I implement something like that? ``` function strip_too_many_communities() { if ( ( bgp_community.len + bgp_ext_community.len + bgp_large_community.len ) >= 100 ) then { bgp_community.empty.except((64511, *)); bgp_ext_community.empty; bgp_large_community.empty; } } ```

The background is that these serve in the [dn42](https://dn42.dev/howto/Bird-communities) as information, how good the connection to the destination is. Therefore I would like to keep these. Does anyone have any ideas on how to do something like this?

Greetings Marek Küthe

-- Marek Küthe m.k@mk16.de er/ihm he/him