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DNS Complexity
ChelleChelle writes "Paul Vixie of Internet Systems Consortium guides us on a journey into the sublime details of the domain name system. Although it contains just a few simple rules, DNS has grown into a system of enormous complexity. This article explores the supposed and true definitions of DNS, and shows some of the tension between the two definitions through the lens of the philosophy of Internet development protocol."
I'm going to risk sounding like an idiot and say that I think it's inhuman that somebody could write an article explaining how DNS works without having at least one diagram in it. I mean, c'mon, I can wade through piles of opaque text with the best of them, but just throw me a bone here, alright?
Been a while since I've seen one of these.
~ a low user id is no indication I have a clue what I'm talking about.
Basically, Vixie's point in the whole article really isn't to rehash how DNS works (although he does basically do that), but to make a rather interesting point about complex systems.
His point is that large systems can become unimaginably complex, even when they begin with a very simple set of rules. Particularly when those rules are vague.
Although he doesn't say it explicitly, I think there are probably some similarities between neutral networks and DNS -- both begin with very simple rules, and then the complexity comes out of the sheer number of connections when you scale it up. Likewise, with DNS, you can have a very simple implementation (say, for a home office) that's quite easy to understand and use. Everything makes sense. It's basically understandable. But then, take that same protocol, even some of the same software, and scale it up to a few billion nodes or whatever DNS has these days, and suddenly the whole thing is so complex, nobody can even begin to really understand it in its entirety. You can't even predict, exactly, how it's going to react to any change -- it's very much like a complex organic system at that point. You can perform experiments on it, and make hypotheses, but even though it's an entirely deterministic system (or ought to be), it acts mysteriously.
"Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
Not sure exactly what your rant was about, but it just sounds like you had crappy support from ISP staff. Not really news, that. There's nothing about the DNS down under that makes it inherently slow. We moved our site recently to a different IP (different ISP, in fact), but we host our own DNS so we had control of the process. I reduced the TTL on the record a few days beforehand, and then really reduced it shortly before we launched the new site, and voila -- the updated record was visible to everyone pretty much instantly. (Except for people who configure their DNS proxies to ignore/override TTL values, but that's their problem.)
Obviously, relying on third parties to do the right thing by you is a crapshoot at the best of times. Not everyone has the luxury of hosting things themselves, though.