adminWhat a CDN Means
A CDN, or content delivery network, places servers between visitors and the origin server. It can cache static files, reduce latency, absorb traffic spikes and provide security features.
Where CDN Sits In The Stack
A CDN sits in front of the VPS. DNS often points traffic to the CDN first, and the CDN then communicates with the origin server.
How CDN Works
When a visitor requests a page or asset, the CDN checks whether it has a cached copy. If yes, it serves the copy from a nearby edge location. If not, it fetches from the origin server and may cache the response.
Why CDN Breaks Websites
A CDN can break a website when SSL modes are wrong, origin IP is blocked, cache rules are too aggressive, DNS records are misconfigured or security rules block real users.
How To Think About CDN
A CDN is not just a speed tool. It becomes part of routing, caching, SSL and security. Any CDN change should be treated as an infrastructure change.
Infrastructure Layer
Cache / CDN
Difficulty Level
Intermediate
Core Concept
A CDN is an edge network that sits in front of the origin server to cache content, reduce latency and add traffic protection.
System Role
It extends website infrastructure beyond one VPS by moving parts of delivery and security closer to visitors.
How It Works
DNS sends traffic to the CDN. The CDN checks cache, serves cached assets when possible, or fetches from the origin VPS when needed.
Connected Components
DNS, CDN edge, origin VPS, Nginx, SSL, cache rules, firewall, static assets, page cache, security rules.
Common Failure Points
Wrong SSL mode, origin unreachable, aggressive cache rules, stale pages, blocked real visitors, DNS misconfiguration, hidden origin errors.
Verification Method
Check DNS target, CDN status, origin reachability, cache headers, SSL mode, firewall rules and whether bypassing CDN reaches the origin correctly.
Basic Commands
curl -I https://example.com;
curl -I https://origin.example.com;
dig example.com;
traceroute example.com;
tail -n 50 /var/log/nginx/access.log