[107707] in North American Network Operators' Group
Re: an effect of ignoring BCP38
daemon@ATHENA.MIT.EDU (Kevin Oberman)
Thu Sep 11 14:24:56 2008
To: Pekka Savola <pekkas@netcore.fi>
In-Reply-To: Your message of "Thu, 11 Sep 2008 20:59:39 +0300."
<alpine.LRH.1.10.0809112050560.14608@netcore.fi>
Date: Thu, 11 Sep 2008 11:24:43 -0700
From: "Kevin Oberman" <oberman@es.net>
X-To: Pekka Savola <pekkas@netcore.fi>
Cc: bmanning@vacation.karoshi.com, nanog@merit.edu, k claffy <kc@caida.org>
Errors-To: nanog-bounces@nanog.org
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> Date: Thu, 11 Sep 2008 20:59:39 +0300 (EEST)
> From: Pekka Savola <pekkas@netcore.fi>
>
> On Thu, 11 Sep 2008, Jo Rhett wrote:
> > On Sep 11, 2008, at 10:10 AM, Valdis.Kletnieks@vt.edu wrote:
> >> By the time you walk our list of upstreams to any of the '5 biggest
> >> anything', you've gotten to places where our multihomed status
> >> means you can't filter our source address very easily (or more
> >> properly, where you can't filter multihomed sources in general).
> >
> > I don't agree with this statement. I hear this a lot, and it's not really
> > true. Being multihomed doesn't mean that your source addresses are likely to
> > be random. (or would be valid if they were)
> >
> > A significant portion of our customers, and *all* of the biggest paying ones,
> > are multihomed. And they might have a lot of different ranges, but we know
> > what the ranges are and filter on those.
>
> If you can manage ACLs for these customers, that's fine. But maybe
> your multihomed customers and '5 biggest anything' customers are
> different. Maybe your multihomed customer has 5 prefixes. The big
> ones could have 5000. That's a pretty big ACL to manage.
It's big, but not un-workable. Just looking at our lists, the longest is
over 212K entries and we have 5 over 5K and 20 over 1K. We would have
even bigger ones if the IRR had more complete information.
I'll admit that doing this for a tier-1 would probably not work, though
I have never been able to try as the requisite information is not
publicly available.
--
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman@es.net Phone: +1 510 486-8634
Key fingerprint:059B 2DDF 031C 9BA3 14A4 EADA 927D EBB3 987B 3751
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