At the Google Public DNS Performance Benefits page, they claim
In Google Public DNS, we have implemented several approaches to speeding up DNS lookup times. Some of these approaches are fairly standard; others are experimental:
- Providing global coverage for proximity to all users.
But if we geo-locate their IP addresses 8.8.8.8 and 8.8.4.4 we see that they are served from Mountain View.
Measuring their latency from Brazil I found out that
- My ISP's DNS answers in 13 ms
- Google's DNS answers in 20 ms
- OpenDNS in San Francisco answers in 130 ms in average
How is that possible? How can they answer from servers in Brazil if the IP routing scheme leads to California?
Best Answer
The addresses are just owned by a company (Google Inc.) located in Mountain View, according to WHOIS information from ARIN. But they are served from whichever location Google decides to announce a route to that range from.
For their DNS servers, Google is using anycast, and the same addresses can in fact be routed to several different locations:
This is the BGP entry for that route: