Today, as part of our efforts to make the web faster, we are announcing Google Public DNS, a new experimental public DNS resolver.
The DNS protocol
is an important part of the web's infrastructure, serving as the
Internet's "phone book". Every time you visit a website, your computer
performs a DNS lookup. Complex pages often require multiple DNS lookups
before they complete loading. As a result, the average Internet user
performs hundreds of DNS lookups each day, that collectively can slow
down his or her browsing experience.
We believe that a faster
DNS infrastructure could significantly improve the browsing experience
for all web users. To enhance DNS speed but to also improve security
and validity of results, Google Public DNS is trying a few different
approaches that we are sharing with the broader web community through
our documentation:
- Speed: Resolver-side cache misses are one of the primary contributors to sluggish DNS responses. Clever caching techniques can help increase the speed of these responses. Google Public DNS implements prefetching: before the TTL on a record expires, we refresh the record continuously, asychronously and independently of user requests for a large number of popular domains. This allows Google Public DNS to serve many DNS requests in the round trip time it takes a packet to travel to our servers and back.
- Security: DNS is vulnerable to spoofing attacks that can poison the cache of a nameserver and can route all its users to a malicious website. Until new protocols like DNSSEC get widely adopted, resolvers need to take additional measures to keep their caches secure. Google Public DNS makes it more difficult for attackers to spoof valid responses by randomizing the case of query names and including additional data in its DNS messages.
- Validity: Google Public DNS complies with the DNS standards and gives the user the exact response his or her computer expects without performing any blocking, filtering, or redirection that may hamper a user's browsing experience.
To get more information on Google Public DNS you can visit our site, read our documentation, and our logging policies. We also look forward to receiving your feedback in our discussion group.
