Meta Platforms Outage: Facebook, Instagram, and WhatsApp Go Dark for 6 Hours

On October 4, 2021, at approximately 11:40 AM EST, Meta Platforms (then Facebook) experienced a catastrophic outage that took down Facebook, Instagram, WhatsApp, Messenger, and Oculus VR services simultaneously. The outage lasted for approximately 6 hours, making it one of the largest internet outages in history. What Actually Happened: The incident was caused by a faulty configuration change to Meta's backbone network routers. During a routine BGP (Border Gateway Protocol) update, engineers accidentally issued a command that removed all routes to Facebook's DNS servers, effectively disconnecting all of Meta's data centers from the internet. Real Impact: - Over 3.5 billion users unable to access Meta services - Facebook's stock dropped by nearly 5% - Businesses relying on Facebook advertising lost millions in revenue - WhatsApp, used by billions for communication, was completely unavailable - The outage affected users globally, not just in specific regions Technical Details: The BGP update caused a cascading failure. When Facebook's DNS servers became unreachable, users couldn't resolve domain names, and even Meta's internal systems couldn't communicate. The company had to send engineers to physical data centers to restore connectivity manually. Lessons Learned: - Implement proper change management procedures with approval workflows - Test configuration changes in staging environments first - Have automated rollback procedures for critical network changes - Implement gradual rollout strategies for infrastructure updates - Maintain physical access to data centers for emergency situations - Design systems with better fault isolation