Subject: Re: [BEHAVE] I-D Action: draft-wing-behave-dhcpv6-reconfigure-00.txt

From: Brian E Carpenter <[email-masked]>
Date: Sat, 22 Oct 2011 13:50:02 +1300

I have a basic question. Why does this draft define a 'normal'
DNS server as one having an IPv4-mapped IPv6 address?

That seems like a completely *abnormal* DNS server for a dual
stack host. A dual stack host should normally have a DNS server
with a regular IPv6 address that will return both A and AAAA
records if they exist. Normally the server will be dual stacked
anyway, and will return exactly the same response whether the
query arrives via v4 or v6.

A DNS server which only has an IPv4 address will also return
A and AAAA records if they exist, so there is absolutely no
difference as far as the dual stack host is concerned anyway.
So what is the point in using the IPv4-mapped address?

Regards
   Brian

On 2011-10-18 11:17, [email-masked] wrote:
> A New Internet-Draft is available from the on-line Internet-Drafts directories.
> 
> 	Title           : DHCPv6 Dynamic Re-Configuration
> 	Author(s)       : Dan Wing
>                           Tirumaleswar Reddy
>                           Prashanth Patil
> 	Filename        : draft-wing-behave-dhcpv6-reconfigure-00.txt
> 	Pages           : 10
> 	Date            : 2011-10-17
> 
>    Some networks are expected to support IPv4-only, dual-stack, and
>    IPV6-only hosts at the same time.  This makes prioritizing the DNS
>    servers for hosts tricky due to a heterogeneous mix of protocol
>    stacks causing optimal behavior to occur only when the host stack re-
>    initializes.  The networks infrastructure is usually well equipped to
>    be aware of single/dual-stack nature of hosts.  This specification
>    extends DHCPv6 so that the DHCPv6 Relay Agent can dynamically
>    influence the priority of DNS servers provided to the host, so that
>    the host can use the optimal DNS server for resolution.
> 
> 
> A URL for this Internet-Draft is:
> http://www.ietf.org/internet-drafts/draft-wing-behave-dhcpv6-reconfigure-00.txt
> 
> Internet-Drafts are also available by anonymous FTP at:
> ftp://ftp.ietf.org/internet-drafts/
> 
> This Internet-Draft can be retrieved at:
> ftp://ftp.ietf.org/internet-drafts/draft-wing-behave-dhcpv6-reconfigure-00.txt
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