[dnsop] DNS Anycast revisited
Todd Vierling
tv at duh.org
Wed May 4 03:52:53 UTC 2005
On Tue, 3 May 2005, Rodney Joffe wrote:
> >> If you check, I think you'll see that he actually said "ultradns's
> >> anycast for .ORG is completely coherent".
> >
> > And last time I checked -- on this list, mind you -- it certainly was not.
>
> If you want to be taken seriously, perhaps you might want to research the
> use of the term coherency in terms of DNS.
> Hint: It doesn't mean that one node responds and another doesn't.
<feedback loop="trollbait">
It certainly breaks coherency in my mind when one query host receives
SERVFAIL for a while, then nothing at all, but another query host is
receiving records that the first query host *should* have seen.
</feedback>
After all these years, I should know better than to feed back the bait.
Maybe it's just fun to do. :)
That said, I'll credit you for catching my brain fart. I read right past
'coherent' in vix's text and saw the phrase '"good" anycast' in relation to
the .ORG zone. It was not technically a *coherency* flaw to which I
referred, but rather a fundamental *architecture* flaw. (It's too bad that
the architectural flaw was never really discussed, or for that matter
subjected to a mea culpa and/or public postmortem. But I suppose that is
the pride/ego component of running such a large zone -- even one intended
for the "public interest".)
I wrote and maintain a query host deterministic, but inter-site coherent,
anycasted DNS server for my $orkplace, so don't presume to tell me what you
think I know. It only makes you look like a holier-than-thou ass [again].
Feel free to feed the trolls elsewhere, though, if you wish; it can be fun
to watch.
--
-- Todd Vierling <tv at duh.org> <tv at pobox.com> <todd at vierling.name>
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