Fix iTunes and Other Slowdowns by Ditching Third-Party DNS Servers [Troubleshooting]

If you’re experiencing slowdowns when downloading large files from iTunes or your Apple TV (or, in certain cases, other places ’round the internet, like YouTube), the issue is likely to be your DNS. AppleInsider explains it best :

Network users are purported to lookup IP addresses from a nearby server, which itself queries and caches answers to name and address lookups from other DNS systems, distributing the workload across the network. CDNs like Akamai, which Apple works with to deliver iTunes downloads, use DNS lookup information to locate where users are, and then optimize content delivery via the nearest available server.

When millions of users all tap into a similar DNS server addresses to solve domain names, as Google DNS does by design, Akamai and other CDNs route content to those users along an analogous path, preventing the network from working optimally. This causes problems not only for Apple’s iTunes, but additionally any other media streaming or download service that uses an analogous CDN approach to distribute downloads.

So, while Google DNS or OpenDNS might need other benefits , they are able to be causing some pretty major slowdowns in other areas. I haven’t experienced this myself, since previously mentioned Namebench already discovered that my ISPs DNS was faster than Google or OpenDNS anyways, nonetheless it could also be something to seem into whenever you’re using a third-party DNS server and you’re having problems (in the event you don’t use iTunes and aren’t noticing other slowdowns, you need to be fine). Hit the link to read more. I’d also recommend reading AppleInsider’s piece on it, since it’s essentially the most informative I’ve read on the subject thus far.

Update: Laura Oppenheimer of OpenDNS wrote in to let us konw that, while Akamai should still cause some suboptimal performance (more outside out the united states than anything), OpenDNS has arrangements with various CDNs that make this mostly a non-issue. Whenever you’re in North America and using OpenDNS, you almost certainly won’t experience the above problem.

iTunes Slowdowns with Google DNS | Joe Maller via Daring Fireball

Apple TV, iTunes Downloads Slowed by Google DNS | AppleInsider