How a Nigerian ISP Accidentally Knocked Google Offline

On November 12, 2018, Google experienced a 74-minute outage due to a "route leak" caused by Nigerian ISP MainOne's accidental misconfiguration of their network. This resulted in unusual routing paths for Google and other networks, overwhelming the intermediary networks and causing services to become unreachable. Route leaks occur when traffic is rerouted outside regular and optimal paths. In this case, China Telecom CN2 did not filter MainOne's incorrect routing information, allowing the misconfiguration to propagate through their network and eventually reach Google. This incident highlights the trust involved in the underlying connections that make up the internet and demonstrates how a routing mistake can have widespread effects. Cloudflare is working with others to improve secure and stable routing practices, such as implementing RPKI validation and encouraging proper filtering of customer routes.