The /24 is as small as it will get before it cuts into profits for the tiny bit
of administration it would take to announce /25, /26. This argument is almost
as old as my kids. Is it fair or just, probably not, but that's they way the
consensus seems to want it.RichardRichard GolodnerInfratection IT Services
-------- Original message --------From: William Herrin <[email protected]> Date:
10/11/22 16:00 (GMT-06:00) To: Matthew Petach <[email protected]> Cc:
[email protected] Subject: Re: any dangers of filtering every /24 on full
internet table to
preserve FIB space ? On Tue, Oct 11, 2022 at 1:15 PM Matthew Petach
<[email protected]> 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 ithas been for decades. It became
the consensus as a holdover from"class C" and remains the consensus because too
many people would haveto cooperate to change it. Indeed, a little over a decade
ago somefolks tried to change it to /19 and then /20 for prefixes outside
"theswamp" and, well, they failed. Likewise, more than a few folksannounce
/26's to their immediate transit providers and they simplydon't move very deep
into the system -- nobody has any expectationthat 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/
