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by pstack
4540 days ago
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But you're just pinging the servers, which is not as informative as the actual response time for returning a lookup. There are exceptions, but ISP-provided nameservers are often problematic. My ISP is one of the two or three biggest in the nation and they intercept NXDOMAIN, their response time is rarely better than OpenDNS or Google's DNS, and they have gone down more than a few times. I've had none of these problems with OpenDNS. One would like to believe that address resolution is such a basic vital service that every provider in every region on the planet both emphasizes and executes it superbly. Unfortunately, they frequently do not. I don't know why using your ISP's nameservers is an assumed thing. Do you assume that everyone uses their ISP's provided email service? Their ISP's complimentary crappy webhosting service? Their ISP's bundled McAffee anti-virus? Of course not. You shop around for the best option for yourself. DNS is the same way. My ISP provides me with it, but so do a lot of other people. Some free and some for pay. When your ISP or another service isn't cutting it for you, you shop around for alternatives. |
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Right. The reasoning is, given that most queries are cache hits (otherwise it's something wrong with the nameserver or environment), lookup times are really negligible if compared to network latency. On our servers cache hits are about 78% of all queries. So, even if 22% of queries are somehow slower (say, latency between ns1.google.com and my DNS is about 47ms, and I guess for OpenDNS it's less than 20ms - so it's, say, 22% of queries are 30ms slower), still it should hold that for a typical user in most cases local ISP nameserver performs better than OpenDNS one.
> they intercept NXDOMAIN
I only wrote about speed, and this is completely another point. Even if they're have faster response times, invalid responses are not worth it, so I'm with you on this. BTW, I remember why I hopped away from OpenDNS - when they introduced premium plans they started to do some NXDOMAIN hijacking and ads injections. Opt-out, but still that annoyed me.
Stability is another issue, too. Guess, OpenDNS should be a clear winner here, too, as they're supposedly having much more redundant nameserver infrastructure than average ISP out there.
> I don't know why using your ISP's nameservers is an assumed thing.
It's not assumed, just a reasonable default. When you set up IP layer, you need NS address(es). You don't need a email or web hosting to participate in basic network connectivity, but you need DNS. Usually, setup is done automatically, using IPCP, DHCP or other sort of configuration protocol, where ISP supplies the client's machine with the necessary information. And obviously, most ISPs provide you with their nameservers, not some third party ones, because in case of failures they can run and fix their own infrastructure, but can only wait for a third party to solve problems on their side and hope it happens soon enough.
In most cases (i.e. unless the ISP is retarded to the extent of filtering out or redirecting DNS packets to another nameservers) you're obviously free to manually override configuration with nameservers of choice. Even encouraged if ISP-provided services are crappy. I've only argued that they should be generally faster, not the other way around.