Redis, Memcached, Varnish, and CDN: What Each Layer Does in Drupal
A practical guide to Drupal cache layers: how Redis, Memcached, Varnish, and CDNs differ, where each sits, and how cache tags and purge keep content fresh.
CDN
How Drupal Handles the Real Client IP Behind Akamai or a CDN
Learn how Drupal determines the real client IP behind Akamai, a CDN, reverse proxies, or Acquia hosting, including AH_CLIENT_IP, trusted headers, and spoofing risks.