Re: Another Big day for IPv6 - 10% native penetration

[Damian Menscher <menscher () gmail com>]

On Mon, Jan 4, 2016 at 2:48 PM, <Valdis.Kletnieks () vt edu> wrote:

> On Mon, 04 Jan 2016 17:23:20 -0500, Christopher Morrow said:
> > https://developers.google.com/speed/public-dns/faq?hl=en
> >
> > there I asked jeeves for ya!
>
> > > So in how many of the 196 or so extant countries does 8.8.8.8 resolve
> to
> > > a host which, when it sends a query up the chain, appears to be in the
> > > same country as the machine that made the original query?
>
> With 43 subnets for servers and only 13 unique airport codes, the
> conclusion
> is that without additional fun and games, locating based on the DNS for
> 8.8.8.8
> will be incorrect for *most* countries.  Probably gets the continent right.


If you're load-balancing by country, you've already lost.  It turns out the
USA has more users than Luxembourg, Samoa, Monaco, Bermuda, and Andorra
*combined*.

On Mon, 04 Jan 2016 14:17:56 -0800, Owen DeLong said:
> > Further, 8.8.8.8 actually fully supports EDNS0 Client Subnet capability,
> so
> > if the geo-IP balancer in question wants, they can eliminate the failure
> mode
> > you are describing in that case.
>
> Which only helps for people using 8.8.8.8. Client Subnet does help the
> issue,
> but it doesn't actually fix it until support is near ubiquitous across
> intermediate nameservers that have clients in other geographic locations...
>
> (I believe that the fact that Google found a need to create EDNS0 Client
> Subnet *at all* is proof that using the DNS address for localization is
> problematic...)
>
> And again - it's still something that needs work upstream to support, and
> you *still* have to deal with the case where the intermediate DNS server
> doesn't do Client Subnet.

Not all auth servers need to support Client Subnet... just those that want
to do DNS-based load-balancing in a more fine-grained level than already
achieved by Google's multiple datacenters.  And while I don't know what
software most companies use for their DNS-based load-balancing, I'd guess
that adding Client Subnet support is a minor feature request relative to
the other required logic.

Damian