IPv6 6to4 and dns
marka at isc.org
Thu Nov 18 19:06:49 CST 2010
In message <4CE5C820.5030205 at mompl.net>, Jeroen van Aart writes:
> What would be the best way to configure your dns once you've set up IPv6
> 6to4? Separate the IPv4 and IPV6 domains or let them be the same?
> That is, use something like example.com for your existing IPv4 address
> and something like 6.example.com for IPv6 (and www.6.example.com etc.)?
> Or is it safe to have both A and AAAA records for the same domain name?
Firstly I would use a tunnel broker instead of 6to4. Easier to
To answer your question you need to do a risk analysis.
Adding a IPv6 address next to a IPv4 address can make connections
to the site appear to be slow when the client side tries IPv6 but
doesn't have a working IPv6 path (this is a very small percentage).
There are some applications that will not fallback to IPv4 if the
IPv6 connection fails (this is also a small percentage again).
ISC publishes both AAAA and A record at the same name. This is
somewhat of a forcing function for broken sites to address their
IPv6 issues. We have been publishing both address for many years
Google on the other had decided to white-list sites that it knows
have IPv6 connectivity and a responsive noc. 6to4 sites don't meet
these requirments. Tunneled sites can.
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742 INTERNET: marka at isc.org
More information about the NANOG