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Link-local IPv6 addresses in the DNS

Mark Andrews <marka@isc.org> Tue, 22 November 2011 03:30 UTC

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To: Brian E Carpenter <brian.e.carpenter@gmail.com>
From: Mark Andrews <marka@isc.org>
Subject: Link-local IPv6 addresses in the DNS
In-reply-to: Your message of "Tue, 22 Nov 2011 15:57:08 +1300." <4ECB0F84.5080802@gmail.com>
Date: Tue, 22 Nov 2011 14:30:03 +1100
Message-Id: <20111122033003.B6D1817DF522@drugs.dv.isc.org>
Cc: 6man <ipv6@ietf.org>, Tomoyuki Sahara <sahara@surt.net>, Kerry Lynn <kerlyn2001@gmail.com>
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On a related issue to link locals in URI's, we don't currently have
a good method of supporting link locals in the DNS.  Sure we can
add them as AAAA records but they are essentially useless as the
scope information is lost.  People keep saying use LL for disconnected
but it just doesn't work without more support.

Mark

DNS
host.example.net. SAAAA  FE80::1 link.example.net.
host.example.net. SAAAA  2001:DB8::1 .		; "." indicates global scope
host.example.net. SAAAA  ::ffff:198.51.100.0 .	; "." indicates global scope
host.example.net. AAAA  2001:DB8::1
host.example.net. A  198.51.100.1

RA LINK-NAME link.example.net
DHCP LINK-NAME link.example.net

getaddrinfo()
AI_FILTERED  filter scoped addresses which don't match a local scope name.
	     Set in AI_DEFAULT.

If you get a response to a SAAAA lookup you don't need to do a A/AAAA lookup
as it is a superset of A and AAAA.

host.example.net SAAAA :: .  indicates a machine that exist but is off net

-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka@isc.org

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