Internet Infrastructure

On October 4, 2021, at 15:40 UTC, Facebook disappeared from the internet. Not just the social network—Instagram, WhatsApp, and even Facebook’s internal tools went dark. Engineers couldn’t access their own data centers. The outage lasted nearly six hours and affected billions of users worldwide. The cause wasn’t a cyberattack or a data center failure. It was a BGP configuration error. Someone issued a command that withdrew the routes Facebook used to announce its presence to the internet, and within minutes, the company’s entire network became unreachable. ...

When you type a URL into your browser, something invisible happens before a single byte of webpage content loads. Your computer must translate that human-readable name into a machine-readable IP address—a process that typically completes in under 100 milliseconds but involves traversing a global hierarchy of servers spanning multiple continents. The Domain Name System (DNS) is often called the “phonebook of the Internet,” but that analogy undersells its complexity. A phonebook is a static directory. DNS is a distributed database with over 1,500 root server instances worldwide, millions of domain records, and caching layers at every level—all designed to resolve billions of queries per day while maintaining consistency across a system that was architected in the 1980s. ...