Subject: [dnsext] Re: DNS64 and SRV records

From: Andrew Sullivan <[email-masked]>
Date: Fri, 12 Feb 2010 13:43:00 -0500

Thanks for the feedback, everyone.  I have concluded we should still
leave the Additional section alone.  Here's some additional text that
I propose to make clearer the reasoning:

           <section title="Handling the additional section" anchor="addl_sec">
             <t>DNS64 synthesis MUST NOT be performed on any records
             in the additional section of synthesized answers.  The
             DNS64 MUST pass the additional section unchanged.</t>

             <t>It may appear that adding synthetic records to the
             additional section is desirable, because clients
             sometimes use the data in the additional section to
             proceed without having to re-query.  There is in general
             no promise, however, that the additional section will
             contain all the relevant records, so any client that
             depends on the additional section being able to satisfy
             its needs (i.e. without additional queries) is
             automatically broken.  An IPv6-only client that needs a
             AAAA record, therefore, will send a query for the
             necessary AAAA record if it is unable to find such a
             record in the additional section of an answer it is
             consuming.</t>

             <t>The alternative, of removing the A records in the
             additional section and replacing them with synthetic AAAA
             records, may cause a host behind a NAT64 to query
             directly a nameserver that is unaware of the NAT64 in
             question.  The result in this case will be resolution
             failure anyway, only later in the resolution operation.</t>

I'll assume there's no objection unless I hear otherwise.

A

-- 
Andrew Sullivan
[email-masked]
Shinkuro, Inc.

---

From: Patrik Fältström <[email-masked]>
Date: Sun, 14 Feb 2010 13:16:42 +0100

> I propose to make clearer the reasoning:

[snip]

> I'll assume there's no objection unless I hear otherwise.

Ok with me.

   Patrik