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.
We hope that you will help us test these
improvements by using
the Google Public DNS service today, from wherever you are in the world. We plan to
share what we learn from this experimental rollout of Google Public DNS with the broader web
community and other DNS providers, to improve the browsing experience for Internet users
globally.
