Using Google DNS Can Slow iTunes Downloads

Utilizing a reliable DNS (domain name server) is important, because it can result in either great speeds on the Internet, or speeds that bring us back to the modem age. For this reason, a lot of people decide to opt out of the DNS their ISP offers, and instead adopt the one that Google provides for free, or OpenDNS (which I used to use with a great deal of success).

Both services are feature-rich and highly configurable, but as it appears, there can be some large caveats. In the case of one man, Joe Maller, he discovered that after purchasing movies off of Apple’s iTunes service, the downloads went painfully slow when using Google DNS. Using that service, he’d download a movie in about 1 – 2 hours, while without it, he could begin watching a film within 20 seconds.

As mentioned, I used to use OpenDNS, and used it for quite a while, and never experienced an issue like that to my knowledge. I’m currently on my ISP’s DNS, and things seem to be fine, although on occasion I do notice some slowdowns in certain things, like when I download from my VPS or games off of Steam. Depending on your situation, location and DNS, you might actually do better or worse with a different solution. But if you do experience slow downloads, like Joe did, then your DNS should be the first place to look.

This totally makes sense. iTunes’ video content is delivered by Akamai who has distributed massive datastores around the world so those large files originate from nearby servers and spend less time getting switched around the network. Akamai somehow uses our DNS routing to determine our location. If Google DNS or OpenDNS routes everyone to Akamai the same way, then those Akamai nodes and the pipes leading to them get overwhelmed.