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Will Vista Overload the DNS?
Jamie Northern writes, "Thanks to new directory software, Windows Vista could put a greater load on Internet DNS servers. But experts disagree over whether we're headed for a prime-time traffic jam or an insignificant slowdown. Paul Mockapetris,inventor of DNS, believes Vista's introduction will cause a surge in DNS traffic because the operating system supports two versions of the Internet Protocol (IPv4 and IPv6). David Ulevitch, chief executive at OpenDNS, a provider of free DNS services, said Vista's use of IPv6 will not disrupt the Internet at large. 'DNS can be improved, but predicting its collapse is just spreading FUD.'"
There would be no news....
Undetectable Steganography? Yep, there's an app fo
just friggin deploy ipv6
Linux and MacOS X are both capable of having both IPv6 and IPv4 stacks, and in many cases this is active by default. Why would Vista cause any more problems?
If you have a good setup then you will have a lookup cache on your local machine storing both IPv6 and IPv4 addresses for each site. Therefore only one lookup should need to be done.
Jumpstart the tartan drive.
For a guy who "invented DNS," he sure doesn't seem to have much of a grasp of how the current DNS infrastructure works.
First off, most DNS servers are very lightly loaded. DNS in general doesn't take a whole lot of traffic (relative to other protocols), and most DNS servers are way overpowered for what they need to do.
Secondly, as the article states, Vista is not going to just blindly do two queries, one IPv4 and the other IPv6, for every request. It is a little more intelligent than that (shocking, I know). For systems that don't have an IPv6 address (which will be virtually all of them given the current adoption rate of IPv6), no IPv6 DNS queries will be done at all.
Linux and other Unix-like OSes have supported IPv6 for years, and they haven't managed to kill DNS yet. Most Vista installations, like most Linux installations these days, are going to have IPv6 disabled anyway, so this is not going to have any real impact at all.
When Vista comes out, it will be introduced gradually compared to the millions of installed Win98/NT/XP systems.
It will take years until/if it reaches considerable marketshare. ISPs have plenty of time to upgrade in the meantime.
It takes a man to suffer ignorance and smile
Be yourself no matter what they say
This has to do with the necessary gradual migration from IPV4 to IPV6, and has nothing to do with Vista. Besides, only routers that support IPv6 will even route the DNS requests to DNS servers. If we want to switch to IPV6, every OS out there is going to have support both in tandem like this. You can't bitch about the slow adoption of IPV6, and then turn around and bitch again when there are insignificant consequences related to the transition.
When working with response time instead of %CPU, the curve is quite different from what one normally sees.
It starts off level, at some number of milliseconds (mostly the round-trip time) and stays that way until the load hits 100%, then increases rapidly and without bound.
For example, if a lookup takes 1/10 second, it will continue to take 1/10 second until there are 10 requests per cpu per second.
After that a queue builds up, and the requests are delayed. Brutally. At a mere 100 requests/second, the delay is 10 seconds, instead of one tenth.
Now imagine that at the huge loads the DNS servers typically handle.
When someone says "they've hit the knee of the curve", he really means "they're about to fall in the toilet" (;-))
--dave
davecb@spamcop.net
It probes for ipv6 first, then falls back to ipv4. This is the default setting for many unix systems as well. You usually find your system running slowly, then find a setting for this and turn it off to eliminate the timeout delay.
As for how big a spike it can cause, see this for the effect of Windows' active directory update scheme on the root servers.
Intron: the portion of DNA which expresses nothing useful.
Toaster: "Well lets just hope you don't get an overload..."
Holly: "What if I do get an overload..."
Toaster: "You'll explode!"
If memory serves, Microsoft had an IPv6 stack for Windows 2000 that you could download from Microsoft's research site. In XP, IPv6 is included, but is disabled by default. A single command enables it. My understanding is that in Vista, IPv6 will be enabled by default.
Honestly, we're going to run out of new IPv4 addresses to hand out in a few years. We need IPv6, and I think Microsoft would be foolish not to enable it by default in Vista.
This is Dan Kaminsky, from the article.
:) Paul knows DNS. It's his creation. But you'll note in this story that Joris Evers can't actually find anyone who agrees with Paul.
Here's what I threw on my blog on this matter. Note, the fact that this got presented as even a debate annoyed me enough to start posting on my site again.
--
Paul Mockapetris says Vista is going to take down the Internet's DNS infrastructure. Paul is the inventor of DNS; I met him at Black Hat last year and was half starstruck, half relieved he didn't hate me for the things I'd done to his creation
There's a reason.
First, while there are indeed a couple underprovisioned name servers, there's far more that have lots and lots of slack capacity. You need slack capacity to deal with shock load. The networks that would fail because of Vista's release, would fail because of a three day weekend.
Second, Vista's not getting deployed all at once. This is no service pack that's deployed to a hundred million desktops via Windows Update! Mockapetris is correct in that there will be a noticable increase in DNS traffic, but that increase will be spread out over the course of a couple years. Slow increases like this tend not to cause the sort of catastrophic failure that Mockapetris refers to.
Finally, and most importantly (in the sense that Mockapetris should know better): Most of the work done to service the IPv6 request, is cached and available to service the IPv4. To complete a DNS lookup, you have to locate a particular server, known as the authoritative server for a domain. The same authoritative server that hosts the IPv6 (AAAA) record also hosts the IPv4 (A) record. So even if Vista sends twice the traffic, the upstream nameserver is certainly not experiencing twice the load.
Full disclosure: Microsoft has had me looking at Vista for much of this year, as part of their "Blue Hat Hacker" external pen-testing squad. But then, Mockapetris has written a really impressive name server for his company, Nominum, that can handle about 4x the load of BIND. But this isn't about who we are; it's about what is or isn't going to collapse. There are things to worry about. This isn't one of them.
As rarely as I can say it, MS seems to be doing EXACTLY what should be done. In fact this could be the tipping point that moves us from IPv4 to IPv6. With 95% of the worlds desktops using IPv4 exclusivly, it made no sense worrying about IPv6 in the routers, and it would have been suicide to go to a pure IPv6 implementation. With Vista, most people will, in a few years, upgrade to Vista, switch to Linux or OSX, or be ready to accept being cut off from direct access to the internet. That means that 95% of the worlds desktops with be IPv6 first and formost, and ISPs can confidently move to an IPv6 backbone without fear of cutting off their customers.
Either way, I don't think that NAT is dead. It might change form a bit, but those in control of the numbers are not likely to just start giving them away, just because they have an over abundence of them any more than the Media Barons just give out music just because they have an over abundance of copies of that.