[dns-operations] An simple observation

Matthew Pounsett matt at conundrum.com
Thu Sep 25 13:26:49 UTC 2014

On Sep 24, 2014, at 21:27 , Davey Song <songlinjian at gmail.com> wrote:

> Hi everyone, I‘m recently doing a little survey on the penetration of IPv6 in DNS system and it's latent problems.
> I find that top websites like Google, Wikipedia,Yahoo already support IPv6 access, but its name servers are still IPv4-only. I'm wondering why? is there any operation consideration or risk in their IPv6 deployment?

There is additional operational complexity in running a dual-stack network, which implies some risk, but in my opinion it’s not serious enough to be a real blocker for most networks.  Some companies may have legacy assumptions in their application that makes adding IPv6 difficult in some way, but from the outside it’s impossible to identify who those networks might be.

Some large companies simply have their own inertia to overcome.  It can take a while to get large re-engineering projects moving in larger companies, and they may need/want to wait until the infrastructure is in place everywhere before turning it on anywhere. 

It’s a little weird to me that google’s authoritative DNS servers are not addressable over v6.  Their Google Public DNS service does operate over v6, so clearly they have the infrastructure in place.  I’m speculating, but perhaps there are bits of their internal CDN-like behaviour that still need to be modified.

In short, no there are no generally applicable technical reasons not to be running v6 on your DNS servers.

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