Google announced a big milestone for their Public DNS service, Google Public DNS. They only started the service in December 2009, but already they are the largest public DNS service in the world, serving 70 billion requests a day, on average.
Shortly after launch, we made a technical proposal for how public DNS services can work better with some kinds of important web hosts (known as content distribution networks, or CDNs) that have servers all of the world. We came up with a way to pass information to CDNs so they can send users to nearby servers.
While I’m sure Public DNS is still a hobby and an interesting research project into the backbone of the internet, it does represent an opportunity for Google from another standpoint.
Consider how you interact with the web today:
Search. People continue to use search instead of typing in the address of a popular website. Google is number one in the Search business. Ad revenue on search results makes up a large part of their income.
Apps. Apps are hot. The use of mobile apps is increasing fast. Google has a finger in a respectable chunk of the mobile Apps business through Android. They are making money through ads from that too, but the dust hasn’t settled yet.
URLs. While the habit of manually entering web addresses is certainly waning in favor of Search and Mobile Apps (like Facebook, Twitter, IMDb, News apps, etc.), they are still built upon the web’s holy trinity: HTML, HTTP, and URLs. These URLs commonly contain hostnames, and each hostname needs to be resolved through DNS.
To turn DNS resolving into a source of ad revenue and data mining, Google could apply a similar technique as OpenDNS when clicking or typing a URL with an incorrect hostname. David Pogue of the NYTimes explains it as follows:
[..] if you type the address of a nonexistent site, OpenDNS throws up the equivalent of Google’s “Did you mean?” screen: a list of sites, provided for (and paid for) by Yahoo, that behave as though you’ve done a search for that term. Presto: more income.
Google is already doing something arguably similar with the address bar in their Chrome browser. By unifying the address bar and the search box into what Google calls the Omnibox, they already redirect a faulty domain name input into a Google search.
However, tweaking the address bar in a Google branded browser that people choose to download, install and use, is one thing. Messing with DNS on a world-wide scale is a completely different thing. Kudos to Google for respecting that line.
If you need any more convincing that DNS is and interesting target, consider the recently defused PIPA and SOPA bills. One of the techniques that these acts were going to enforce on ISPs is DNS filtering. In essence, the bills would have required ISPs to tweak their DNS servers to stop resolving requests for infringing domains.
In the face of these threats, having popular open DNS services like those provided by Google and OpenDNS is far from the blessing they appear to be. Who says these new laws would not apply to Google or OpenDNS? The only way for the internet to survive attacks like these, is a large robust network of independently run DNS servers.
If my ISP had decided to disrespect me by poisoning their DNS service, I would think about switching to another ISP first, before considering other alternatives.