Re: bgp_next_hop check?

On May 29, 2018 8:42:22 PM GMT+02:00, Job Snijders <job@instituut.net> wrote:

Dear BIRD devs,

On https://gitlab.labs.nic.cz/labs/bird/wikis/BGP_filtering I see the following curious snippet:

function xx() { ... if bgp_next_hop != from then return false; ... }

What in the above example does "from" mean? Is "from" some kind of magic keyword that expands into something?

Yes. It expands to the author of the route (IP of its sender). Therefore this check is to filter out routes with other next hop than the sender herself as this is probably some scam or misconfiguration. Maria