[dns-operations] opting in to stupid DNS tricks

Joseph S D Yao jsdy at tux.org
Mon Feb 21 20:03:09 UTC 2011

On Mon, Feb 21, 2011 at 07:46:03PM +0000, Patrick W. Gilmore wrote:
> On Feb 21, 2011, at 18:57, Joseph S D Yao <jsdy at tux.org> wrote:
> >> However, just to clear up a few things, CDNs are not the only companies that get geo-localization wrong.  And there is the fact most web page localizations (including all the Akamai ones I've seen) use the client IP address, not the name server IP address.  But please don't let things like facts get in the way of rant against CDNs.
> > 
> > I am curious about how this works.  As I have observed it, I thought
> > that Akamai returned an IP address of a local mirror.  [At least, one of
> > their services does.]  In that scenario, the end client's IP address is
> > never seen: ...
> You are conflating which web server serves the content with what content is served.
> Yes, Akamai returns a different IP address for each query depending on your (topological) location, the network conditions at the time, server load, etc.  However, that is just the hostname.  Once you ask for a web page, the "localization", e.g. the banner add for the pizza place down the street, is determined by the IP address of the machine that does the HTTP GET.  (At least for all localizations I have seen.)
> Hence my comment that Akamai, and as far as I know most large websites, do not use the location of the name server for things like language choice. 

It appears that when you were using the term "localization" you were
referrring only to the locale-specific attributes of the returned data.
I was probably confused because the discussion up to that point had
primarily been discussing the location of the Web server itself.  So,
still thinking "location", I read the word "localization" the way I read
"use" whenever I see "utilize".  [The cases in which "utilize" means
something different from "use" are not common, in practical use.]

Thus you thought I was combining the two issues, when I wasn't even
recognizing one.

I think we can agree that the IP address returned has nothing to do with
the end user's location, geographical or topological, and everything to
do with the last-hop resolving name server's location.  Which was the
point to which ISTM you were responding, or perhaps not responding.

** Joe Yao				jsdy at tux.org - Joseph S. D. Yao

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