Murphy's Law: Do you Really Need Google? Benchmark Your DNS!

TheMurph

I'm sure many readers of Maximum PC--this one included--have jumped onboard the Google DNS ship, lured either by promises of increased speed versus one's own DNS server or a simple fascination at anything Google does. Fair, at least with the latter. Because it would be erroneous to just switch over to an alternate DNS server without any kind of assessment that what you're doing is actually the best-case scenario for your home or office setup.

That said, it's important to first give props to Google for delivering a DNS service that appears to be free of any kind of takeovers or unexpected redirects. Just try hand-pounding your keyboard after clicking on your browser's address board, then hit enter. If the resulting "fasdfljsajdf.com" isn't actually a Web site, you'll notice how... nothing happens, save for the standard "what are you doing?" error page (depending on your browser of choice). That's a bit different than OpenDNS, which routes you over to one of its own landing pages--oddly, a rebranded version of Yahoo! search--that's stacked with advertising related to whatever it is you mistyped. Weak.

Redirects aside, it's important to know exactly what you're getting into when you start fussing around with going a step beyond your ISP's default DNS servers. Like a tangible product review, you should really assess what you're gaining and losing through the use of either OpenDNS or Google DNS from both a performance and features standpoint.

Performance

Some early benchmarks indicate that Google DNS delivers both a best-case and worst-case scenario for Web site lookups. Vaibhav Gadodia over at Habitually Good has run some benchmarks on Google DNS and discovered that it performs slightly worse than OpenDNS, but slightly better if you remove a few larger spikes, or DNS delays, from Google's testing. Keep in mind, however, that Gadodia is testing this setup in India, comparing the lookup times of 100 different domains to generate his performance graphs. On the whole, OpenDNS appears to offer more consistent performance than Google DNS based on the standard deviation of the scores--how far each time is, on average, from the overall average of all the times.

I ran a few of my own benchmarks between both services to get a feel for performance based on my San Francisco Bay Area location. In the appropriately named " DNS Benchmark " application, I received the following results:

My Comcast DNS server (Comcast, San Jose)
Cached: 13ms
Uncached: 57ms
DotCom Lookup: 41ms

OpenDNS
Cached: 17ms
Uncached: 73ms
DotCom Lookup: 118ms

GoogleDNS
Cached: 39ms
Uncached: 111ms
DotCom Lookup: 165ms

The results are interesting. Here are some quick definitions for what the benchmark tests. The "Cached" result refers to queries that are answered by the server's local name cache--if you're trying to access a popular Web site, odds are good that the DNS server knows exactly where you want to go without querying other nameservers on the internet to figure out what it is you're trying to access (which would be represented by the "Uncached" result). DotCom lookup refers to how much time it takes the DNS server to connect to a particular site's nameserver, which then turns over the IP address of said site to the DNS server.

Whoo. That's a lot.

Anyway, it appears that the Comcast DNS out of San Jose, California is a bit faster for me then even Google's DNS, which ranks third in this small fraction of tested DNS services. Again, this is based on my own connection and location--results may vary for you. And, in testing for the speediest DNS server to use, you'll want to run more than one benchmark. In this case, I also launched a series of tests using the Namebench application just to get additional verification regarding local DNS speeds. Here's what I found:

My Comcast DNS server (Comcast, San Jose)
Average response time: 31.46 ms
Minimum response time: 0.77 ms
Maximum response time: 225.36 ms

OpenDNS
Average response time: 45.45 ms
Minimum response time: 16.0 ms
Maximum response time: 343.75 ms

Google DNS
Average response time: 98.87 ms
Minimum response time: 33.87 ms
Maximum response time: 2153.35 ms

Oof. Look at that last result--that's quite a spike to deal with if Google DNS actually takes that long to pull up a site on occasion. So, given the lag between my normal DNS server and both OpenDNS and Google DNS, why would I want to switch to either of these services? In a word, features. While most of Google's DNS optimizations for security come on the back-end, OpenDNS actually allows you to set up a blocking mechanism that will physically prevent you from accidentally surfing over to sites that have been deemed security nightmares. You can set this filtering level to one of five pre-designated settings, or establish your own mix-and-match of different problematic categories you want to block out.

In addition, the service will fix common typos you make when entering site names (maximumcp.com instead of maximumpc.com, for example). And should you update your network's IP address with OpenDNS or use the handy application that fires off this information for you whenever you turn your computer on, you'll be able to access a wealth of statistics about your general surfing habits. Best of all, you can also set up keywords akin to Mozilla Firefox's smart keywords: Type a word into the address bar of your browser and, if you've established a connection between said word and a particular Web site, you'll go right to said Internet address. Neat, huh?

I don't mean this to be an outright condemnation of Google DNS, nor an essay of praise for OpenDNS. If anything, you'll want to choose the DNS service that makes the most sense for your habits. Run the benchmarks, figure out how you can maximize the performance of your Web browsing, and then decide which service makes the most sense based on your need for extra features or outright speed. As Captain Planet says, the power is yours!

David Murphy (@ Acererak) is a technology journalist and former Maximum PC editor. He writes weekly columns about the wide world of open-source as well as weekly roundups of awesome, freebie software. Befriend him on Twitter, especially if you have an awesome app or game you're dying to recommend!

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