Re: A6 record status

Mark Andrews <marka@isc.org> Fri, 12 August 2011 07:11 UTC

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To: Sheng Jiang <jiangsheng@huawei.com>
From: Mark Andrews <marka@isc.org>
References: <5D36713D8A4E7348A7E10DF7437A4B9201228398@SZXEML506-MBS.china.huawei.com> <4E3F5166.8000605@gmail.com> <5D36713D8A4E7348A7E10DF7437A4B9201228515@SZXEML506-MBS.china.huawei.com> <750E838E-3962-4893-A2D0-012576A1BF36@ecs.soton.ac.uk> <EMEW3|7906899305f1bb5341fe3f32269a1f49n779ac03tjc|ecs.soton.ac.uk|750E838E-3962-4893-A2D0-012576A1BF36@ecs.soton.ac.uk> <4E406303.4040603@gmail.com> <5D36713D8A4E7348A7E10DF7437A4B920122B288@SZXEML506-MBS.china.huawei.com> <4E43378D.8070505@gmail.com> <5D36713D8A4E7348A7E10DF7437A4B920122B2E1@SZXEML506-MBS.china.huawei.com> <4E4345BB.5060103@gmail.com> <5D36713D8A4E7348A7E10DF7437A4B920122B36A@SZXEML506-MBS.china.huawei.com> <4E445261.3040506@gmail.com> <C0E0A32284495243BDE0AC8A066631A8895615@szxeml526-mbx.china.huawei.com> <22F6318E46E26B498ABC828879B08D4F1786A07E@TK5EX14MBXW652.wingroup.windeploy.ntdev.microsoft.com> <20110811234742.C922612BD870@drugs.dv.isc.org> <4E447C7E.30202@gmail.com> <20110812045644.39BF212BFBCF@drugs.dv.isc.or g> <5D36713D8A4E7348A7E10DF7437A4B920122BD2C@SZXEML506-MBS.china.huawei.com>
Subject: Re: A6 record status
In-reply-to: Your message of "Fri, 12 Aug 2011 06:12:40 GMT." <5D36713D8A4E7348A7E10DF7437A4B920122BD2C@SZXEML506-MBS.china.huawei.com>
Date: Fri, 12 Aug 2011 17:11:31 +1000
Message-Id: <20110812071132.0B6CD12C1D5B@drugs.dv.isc.org>
Cc: Christian Huitema <huitema@microsoft.com>, Tim Chown <tjc@ecs.soton.ac.uk>, 6man <ipv6@ietf.org>, Brian E Carpenter <brian.e.carpenter@gmail.com>, Tina TSOU <Tina.Tsou.Zouting@huawei.com>
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In message <5D36713D8A4E7348A7E10DF7437A4B920122BD2C@SZXEML506-MBS.china.huawei
.com>, Sheng Jiang writes:
> > In message <4E447C7E.30202@gmail.com>, Brian E Carpenter writes:
> > > On 2011-08-12 11:47, Mark Andrews wrote:
> > > > I think it is make work
> > >
> > > That's why I am only suggesting an IESG decision, not a draft
> > > and an RFC.
> > >
> > > > and won't change the amount of confusion.
> > > > In addition A6 allows compresssion of the domain name in the rdata
> > > > so it can't be treated as unknown (i.e. a opaque blob) by
> > nameservers.
> > >
> > > If it's historic, servers shouldn't even contain any A6 records,
> > > surely?
> > 
> > Making something historic doesn't remove the old software or the
> > old records.  Removing knowledge of A6 from recursive server will
> > result in garbage A6 records being delivered to old clients that
> > are A6 aware.  A6 aware clients still work as they ask for both
> > AAAA and A6 records.
> 
> Yes, your statement are right. However, the case of A6 is there are few curre
> nt A6 software or records. As far as I know, there are no commercial A6 suppo
> rts in the current global DNS system. A6 only existed in some experimental sy
> stem, like 6net. So, what we are worried here is not these existing A6. By mo
> ving A6 into historic, we are preventing any NEW A6 implementation or deploym
> ent.
> 
> Sheng

The root servers are getting 100's of A6 q/s (~20:1 AAAA:A6
<http://k.root-servers.org/statistics/GLOBAL/daily/>).  There is
still a very large base of A6 using software out there regardless
of whether they are getting NODATA responses or not.

I don't know what percentage of responses are NODATA and what have
actual A6 records.  I do think we need to know answers to these sorts
of questions.

Mark

> > One needs a phase out plan if you want to remove A6 support and it
> > is likely to need to be decades long given how long people run old
> > nameservers for.
> > 
> > > > If one wants to do something about IPv6 addresses in the DNS add
> > > > support for scoped addresses.  Link-local could then be useful.
> > >
> > > Different topic, and I suspect much more complex.
> > >
> > >    Brian
> > --
> > Mark Andrews, ISC
> > 1 Seymour St., Dundas Valley, NSW 2117, Australia
> > PHONE: +61 2 9871 4742                 INTERNET: marka@isc.org
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-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka@isc.org