[dns-operations] Vista implements a bizarre DNS server selection algorithm from RFC3484?

Joe Greco jgreco at ns.sol.net
Fri Mar 6 14:18:33 UTC 2009

> On Thu, Mar 05, 2009 at 07:25:41AM -0600,
>  Joe Greco <jgreco at ns.sol.net> wrote 
>  a message of 65 lines which said:
> > I know it was discussed at some point, there are some practical
> > strategies to discover the public IPv4 address you're using on the
> > Internet, was any of that ever collected into an RFC?
> Yes. The main one is STUN, RFC 5389. Several related RFC and I-D are
> made by the courageous BEHAVE working group
> <http://www.ietf.org/html.charters/behave-charter.html>, which we can
> all thank.

Ah, yes, thought I had seen that somewhere.

> Whether Visa should have used STUN before extending RFC 3484 to IPv4
> is another matter...

Yes, it probably should have, but with some additional complexity.

This whole thing is a specific case of a much more generalized problem,
which of course is determining the general topology of the network for
efficiency and performance purposes.  We've seen this repeatedly.  Gamers
want the closest server for interactive responsiveness (low bandwidth/high
PPS); many games simply use ping time.  P2P networks have attempted various
strategies, and may simply not care too much if they're fetching content
from across an ocean even when the data is available from a closer source.
We've saddled large file downloaders (think OS ISO images) with having to
determine the best site to use.  The vastly varying speeds of FreeBSD FTP
sites is a great example.

Given that IP(v4) space is delegated in a regional manner, it wouldn't be
completely insane to use that knowledge to try to optimize for a closer
server.  Coupled with the client's *actual* IP address, one could then use
it to pick the closer server.

Of course, a GSLB system at the other end may be trying to do the same
thing, based on the IP address of the recurser in use, which we all know
has some ins and outs.

I guess the real question is why we have failed to design and implement
a standard to allow both clients and servers to specify, learn, and/or 
infer some useful information about topology and performance that would
allow programs to automatically make intelligent decisions in an automated
manner that would also allow configuration by administrators.

Oh, wait, this is the Internet, what was I thinking.  ;-)

... JG
Joe Greco - sol.net Network Services - Milwaukee, WI - http://www.sol.net
"We call it the 'one bite at the apple' rule. Give me one chance [and] then I
won't contact you again." - Direct Marketing Ass'n position on e-mail spam(CNN)
With 24 million small businesses in the US alone, that's way too many apples.

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