I recently read an article about a company which offers free, alternative DNS look-up servers. The company is called OpenDNS http://www.opendns.com/.

They make the following statement:

"The speed of your DNS service determines how quickly websites load for you. That's why you want your DNS service to be blazing. OpenDNS is so fast because we run some of the largest DNS caches around and do it on our own high-performance network. "

Realistically, what percentage of the typical page load time is consumed by accessing the DNS look-up server? Would a "blazingly" fast DNS service make any noticeable different in page load times? Can PingPlotter show the time consumed by DNS look-up?

Thanks

Don

Hi, Don.

DNS lookup speed is part of the overall page load time and reducing it may or may not be noticable - depending on how fast your current DNS servers are providing DNS information. If your ISP is providing DNS for you and it's working the way it's supposed to, then any DNS lookup shouldn't be adding much time to any page load.

Each DNS lookup only needs to be done once, so on a normal page with data from only a couple different domains, the DNS server isn't going to be much of an impact, unless it's really slow *or* there are a ton of DNS lookups to do on the same page (like on Myspace or somewhere that's bringing together data from a lot of different sources).

PingPlotter really doesn't do much for you with DNS testing because any lookup is going to be cached at the server (and your computer) so doing repeated lookups of the same data (which is what PingPlotter is so good at) isn't really the right way to test unless you're only interested in the network part of the DNS lookup.

The latest beta of PingPlotter does do UDP DNS testing, but it focuses just on the network component of DNS, and not the whole DNS process.

I'd probably look for a tool that is built for DNS performance testing (like the one here: http://www.georgebreese.com/net/software )and see if your servers are performing well or not. I've never used this type of tool, but it looks promising.

Good luck!
Pete

Thanks Pete,

Actually, I have no personal interest in the subject. My suspicion was as you indicated - DNS look-up time is not a significant portion of the typical page load time.

I asked because I knew you could give me an authoritative answer. There was an article today in the New York Times on the subject, which begins by stating that the founder of OpenDNS.com "is trying to turn two numbers into a multimillion-dollar business," the two numbers being the addresses to his DNS servers. There seemed to be a bit of hyp there, thus my question to you.

Thanks again,

Don

Well ...

I have a buddy that switched DNS servers a few months ago and he says things feel snappier. Is it overwhelmingly better? No - but "snappier" can be good. I think that in most cases, ISP-provided DNS services are good enough that replacing them won't significantly improve the browsing experience. It definitely won't improve your download speeds, VoIP line quality, or stock trades. I don't have any "authoritative" evidence on this topic, just a lot of years troubleshooting networks and rarely finding DNS problems of a scale that are very discernible.

I'm sure there are numerous cases where getting a new DNS server is warranted. I'm also sure that the OpenDNS marketing / PR machine is taking full advantage of any examples that show this. The quote you included from their web site is technically true, but it is also easily interpreted in a way that makes the situation seem worse than it really is. We hear a *lot* about network problems here, and DNS problems are not often an issue.

- Pete