On Thu, Aug 25, 2022 at 10:58 AM Tom Beecher <beecher@beecher.cc> wrote:
If I was running an edge device with a limited FIB, perhaps I might drop it to save memory. If I had beefier devices, perhaps I would just depref it.
Hi Tom, Neither of these answers make much sense to me. If you're using a default route to overcome a limited FIB, you want a more reliably chosen set of routes to filter than the stray error route that shouldn't have reached you. Nearly all paths on the Internet are still under 64 hops wide (packet TTL of 64) so finding a non-customer route with more than double that number of elements in the AS path suggests someone tried to do something fancy in a local environment and it leaked. Not only is it reasonably safe to discard such routes, long AS paths have been responsible for triggering bugs in multiple BGP implementations. Failing to filter it may actually be harmful to folks downstream from you. Regards, Bill Herrin -- For hire. https://bill.herrin.us/resume/