DNS Behaviour - Dual Stack Clients

[Paul Stewart]

Thank you for the reply... so just to clarify further...

A remote client or name server queries our nameserver (which is only reachable via IPv4).  Our name server replies with A and AAAA records in the lookup.  If the remote client is IPv6 capable will it ignore the AAAA information because it was only able to get the query answered via IPv4?  I believe this is what you're saying - again, just looking to clarify ;)

Appreciate it,
Paul


-----Original Message-----
From: ipv6-ops-bounces+paul=paulstewart.org at lists.cluenet.de [mailto:ipv6-ops-bounces+paul=paulstewart.org at lists.cluenet.de] On Behalf Of Doug Barton
Sent: March-18-10 6:38 PM
To: ipv6-ops at lists.cluenet.de
Subject: Re: DNS Behaviour - Dual Stack Clients

On 03/18/10 15:27, Paul Stewart wrote:
> Hi folks..
> 
> Pardon me if this is a "basic" question but trying to see if I
> understand DNS for IPv6.... we have dual-stack running in our core
> and distribution networks.

Yay!

> Unfortunately our DNS servers are behind load balancers that do not
> support IPv6 yet ;(

Boo!

> If I load the reverse IPv6 zone and put forward AAA entries into BIND
> it answers fine locally - what happens with a dual-stack client when
> they want to do a IPv6 authoritive lookup?  Will the dual-stack
> client connect on IPv4 and be able to still receive *and use* IPv6
> records (via IPv4)?  Or is this client dependant on how it's
> configured?

... but seriously folks, the client and their resolving name server are
almost always completely independent entities. If YOUR name server only
has IPv4 address entries (which it should from what you describe) the
other name servers in the world will only try to connect to it via IPv4.
The fact that you return AAAAs for your dual-stacked hosts has nothing
to do with how the remote nameservers get the answers.


hth,

Doug

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