On Tue, Oct 11, 2022 at 1:15 PM Matthew Petach <mpet...@netflight.com> wrote: > Wouldn't that same argument mean that every ISP that isn't honoring > my /26 announcement, but is instead following the covering /24, or /20, > or whatever sized prefix is equally in the wrong? > > What makes /24 boundaries magically "OK" to filter on,
Hi Matthew, /24 is the consensus filtering level for Internet-wide routes and it has been for decades. It became the consensus as a holdover from "class C" and remains the consensus because too many people would have to cooperate to change it. Indeed, a little over a decade ago some folks tried to change it to /19 and then /20 for prefixes outside "the swamp" and, well, they failed. Likewise, more than a few folks announce /26's to their immediate transit providers and they simply don't move very deep into the system -- nobody has any expectation that they will. > To wrap up--I disagree with your assertion because it depends entirely > on a 'magic' /24 boundary that makes it OK to filter more specifics smaller > than it, but not OK to filter larger than that and depend instead on covering > prefixes, without actually being based on anything concrete in BGP or > published standards. Got any better reasons besides disliking the consensus? Regards, Bill Herrin -- For hire. https://bill.herrin.us/resume/