Re:Italy Approves ‘Google Tax’ on Internet Companies
by waps on Tuesday December 24, 2013 @11:41PM
(#6962200)
DNS requests do not specify who requests the IP address. So think of the problem a CDN has : it has to identify the requesting party's geographical location, based on where the request comes from.
If it comes from 8.8.8.8 then you've got no clue. If it comes from an ISPs recursive DNS you can guess : most ISPs have limited geographical reach. If it comes from Telecom Italia's DNS servers, it's either Italy or the middle east (and due to seabone, you will feed them the same entry point to the CDN)
When a request comes from Google (or for that matter, another global network like Level3) you have a problem. The request doesn't specify where the client is, and the request will be cached. So what do you do ? Which entrypoint do you feed it ? You're essentially stuck with anycast, and that has it's own problems.
Is every CDN's depended on privileged position inside ISP's? DNS by design is on the edge of the network, and works perfectly fine regardless of who ask the server for a lookup. If the DNS server want to do geo-depended service, they only have to use geo-ip to figure out where a request is coming from and sending the closest geo-located server as answer. You can even do it with http server and redirects.
ISP based dns resolver existed because early networks took time and money to send a single package back and forth from the client to the server. Those economics should not be considered in 2013. Having a third-party doing your dns resolving is like calling the local police office for directions when driving. Antiquated, unnecessary, and not very safe any more for privacy reasons.