Re: Proposed optimization to multicast DNS

Matt Crawford <crawdad@fnal.gov> Tue, 17 July 2001 15:15 UTC

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From: Matt Crawford <crawdad@fnal.gov>
To: Brian Zill <bzill@microsoft.com>
Cc: namedroppers@ops.ietf.org, Jun-ichiro itojun Hagino <itojun@iijlab.net>, David Terrell <dbt@meat.net>
Subject: Re: Proposed optimization to multicast DNS
In-reply-to: "17 Jul 2001 00:15:46 PDT." <CB7153628BD3724096258CBFD70AA891015CE012@red-msg-04.redmond.corp.microsoft.com>
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Date: Tue, 17 Jul 2001 07:49:06 -0700
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    listen on).  Also, Matt's solution addresses the issue raised by David
    Terrell (answer: lowercase the alphabetic characters before hashing).

More precisely, convert to canonical form as defined by DNSSEC ...

    When the Subject is a domain name, either fully-qualified or
    single-component, and the Querier does not have a unicast address
    for the target node, the query MUST be sent to a link-scope
    multicast address formed in the following way.  The Subject Name is
    converted to canonical form, as defined by DNS Security [2535],
    which is uncompressed with all alphabetic characters in lower case.
    (If additional DNS label types for host names are defined, the rules
    for canonicalizing those labels will be found in the defining
    specification.)  Compute the MD5 hash [1321] of the first label of
    the Subject Name -- the portion beginning with the first one-octet
    length field and up to, but excluding, any subsequent length field.
    Append the first 32 bits of that 128-bit hash to the prefix
    FF02:0:0:0:0:2::/96.  The resulting multicast address will be termed
    the "NI Group Address" for the name.


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RE: Proposed optimization to multicast DNS Brian Zill
Re: Proposed optimization to multicast DNS Matt Crawford