What the Azure outage revealed about internet fragility

On October 29, 2025, Microsoft Azure experienced a significant global service disruption triggered by a configuration change in its edge-delivery network fabric. The incident began at approximately 16:00 UTC, when the company's global content delivery network (CDN) service, Azure Front Door (AFD), began rejecting or timing out requests across its international fleet.

A modern CDN is a globally distributed network layer positioned between users and application backends. Instead of sending traffic across multiple independent internet networks, it terminates user connections at geographically dispersed points of presence and forwards them across a single private backbone under unified control. This enables consistent routing behavior and can improve performance, availability and security. Static and semi-static content may be cached at the edge to reduce latency and offload origin infrastructure. Advanced CDNs also typically incorporate distributed denial of service (DDoS) attack protection, application-layer firewalling and other security controls.