CDN (Content Delivery Network)
A network of edge servers that cache content near users, cutting latency, absorbing traffic spikes and adding a security and TLS-termination layer in front of the origin.
What it is
A CDN places copies of your content in data centres worldwide. A request is served from the nearest edge, so bytes travel less distance. CDNs also terminate TLS, cache aggressively per caching headers, and shield the origin from traffic spikes and attacks.
Why it matters
- Edge caching dramatically reduces latency and origin load.
- CDNs add DDoS protection, TLS termination and often a WAF.
Common mistakes
- Caching personalised or authenticated responses at the edge, leaking data between users.
- Not setting correct Cache-Control, so the CDN cannot cache effectively.
How WebInspect checks this
- WebInspect detects the CDN in front of a site from response headers and network signals, and reports it.