Tianhao Chi and Puneet Sood, Google Public DNS The Domain Name System (DNS) is a fundamental protocol used on the Internet to translate human-readable domain names (e.g., www.example.com) into numeric IP addresses (e.g., 192.0.2.1) so that devices and servers can find and communicate with each other. When a user enters a domain name in their browser, the DNS resolver (e.g. Google Public DNS) locates the authoritative DNS nameservers for the requested name, and queries one or more of them to obtain the IP address(es) to return to the browser. When DNS was launched in the early 1980s as a trusted, content-neutral infrastructure, security was not yet a pressing concern, however, as the Internet grew DNS became vulnerable to various attacks. In this post, we will look at DNS cache poisoning…