Re: [v6ops] Some stats on IPv6 fragments and EH filtering on the Internet

Mark Andrews <marka@isc.org> Tue, 05 November 2013 00:13 UTC

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To: Fernando Gont <fgont@si6networks.com>
From: Mark Andrews <marka@isc.org>
References: <5278275C.50206@gont.com.ar> <alpine.DEB.2.02.1311050028410.26054@uplift.swm.pp.se> <52783535.9030200@si6networks.com>
In-reply-to: Your message of "Mon, 04 Nov 2013 16:00:53 -0800." <52783535.9030200@si6networks.com>
Date: Tue, 05 Nov 2013 11:12:43 +1100
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Cc: IPv6 Operations <v6ops@ietf.org>, "6man@ietf.org" <6man@ietf.org>, Fernando Gont <fernando@gont.com.ar>
Subject: Re: [v6ops] Some stats on IPv6 fragments and EH filtering on the Internet
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In message <52783535.9030200@si6networks.com>om>, Fernando Gont writes:
> On 11/04/2013 03:32 PM, Mikael Abrahamsson wrote:
> >>
> >> Certainly there's *much* more work to be done in this area, but I
> >> thought that this could be good food sfor some of the discussions that
> >> we were having on the topic.
> > 
> > "Operators are known to filter IPv6 fragments". This kind of writing
> 
> Isn't there a v6ops I-D with similar wording?
> 
> 
> > implies intent, right? 
> 
> mm... as far as discussion on a number of forums went, apparently
> there's intent to do so.

There is also often no intent.  The defaults drop fragmented packets
any you have to explicitly pass them.

> > Most of the "filtering" I would say is due to
> > default device behavior, where no intent exists on the operator.
> 
> Data? References?

*BSD firewall drop by default.  For all flavours of firewall supported.
e.g. ipfw, ipf.
 
> > So I'd
> > rather see this changes to "IPv6 fragment header packets are having a
> > severely degraded network experience" or something like that.
> 
> Well, the preso is out there, already. :-(
> 
> 
> 
> > Otherwise, great work. I would like to see traceroute or alike done with
> > these kinds of packets headers also, to see where packets are dropped.
> 
> Yep. This is in my TODO list. Hopefully we will cooperate with Tim
> (Chown) et al to take these measurements further.
> 
> Thanks,
> -- 
> Fernando Gont
> SI6 Networks
> e-mail: fgont@si6networks.com
> PGP Fingerprint: 6666 31C6 D484 63B2 8FB1 E3C4 AE25 0D55 1D4E 7492
> 
> 
> 
> 
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-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka@isc.org