How Verizon and a BGP Optimizer Knocked Large Parts of the Internet Offline Today

Great post from Cloudflare about a large scale routing issue that impacted some big sites on the Internet. it is amazing how much impact a small error like this can have.

Today at 10:30UTC, the Internet had a small heart attack. A small company in Northern Pennsylvania became a preferred path of many Internet routes through Verizon (AS701), a major Internet transit provider. This was the equivalent of Waze routing an entire freeway down a neighborhood street — resulting in many websites on Cloudflare, and many other providers, to be unavailable from large parts of the Internet. This should never have happened because Verizon should never have forwarded those routes to the rest of the Internet. To understand why, read on.

Yikes. 😬