~35 min read · updated 2026-05-10

DNS and CDN fundamentals

The original Cloudflare products — DNS, the CDN, caching, TLS modes — set up correctly the first time.

This module is being expanded.

Coming in the next revision:

  • DNS basics on Cloudflare — nameserver delegation, the “orange cloud” proxy mode, what happens when proxying is on vs off.
  • 1.1.1.1 — Cloudflare’s public resolver, what it is, and why DNSSEC matters.
  • TLS modes — Off / Flexible / Full / Full (Strict) / Strict (Origin Pull). What each actually means at the byte level. Almost everyone should be on Full (Strict).
  • Caching rules — page rules vs the newer cache rules engine. Cache-Control respect, custom cache keys, edge cache TTLs.
  • Argo Smart Routing — what the optimization does and when it pays off.
  • Load Balancing — origin health checks, weighted routing, geo-steering.
  • Stream and Images — Cloudflare’s video and image-resizing products for media-heavy sites.

Next: Module 03 — Cloudflare Tunnel.