David At 08:32 p.m. 12/12/2009, you wrote:
All,
With the recent announcement of Google's public DNS servers, I am worried about operators of CDN who may rely on DNS queries for geo-location (Akamai comes to mind). Today it is reasonable to assume DNS queries from ISP1's name servers (or address block in general) are probably from a client within the ISP1 network. With public DNS servers it gets a whole pile harder.
Akamai does use DNS resolvers as a part of its CDN. Others tend to use anycast routing. It is more popular as it is more direct, rather than waiting on DNS responses and traffic hand offs. I wouldn't say Akamai is alone, but most newer CDNs use Anycast.
I think this is something for the community to carefully consider, especially given how CDN like Akamai can dramatically reduce traffic across peering links for a number of NZ ISP. I'm not trying to condone the idea of public DNS servers or comment on the motivation behind Google and others operating them, but just focus on the impacts.
Does any one else see a cause for concern?
Most holders of large or valuable content use two geo fencing techniques. After the initial connection, theres often one coded into the player, looking at giveaway clues on your PC. DRM systems also have their own methods of geo tracking. So on a typical site you may have 3 systems checking you out. And its known that there is "leakage". Richard