DNS Propagation Demystified: Why DNS Changes Propagate Slowly Across Global Resolvers

DNS propagation is fundamentally misunderstood in web operations. While DNS changes appear instantly live on authoritative nameservers, recursive resolvers worldwide continue serving cached responses until their TTL expires—potentially for up to 72 hours. Understanding TTL mechanics, caching layers, and the resolution flow enables teams to execute DNS migrations with near-zero downtime and avoid costly propagation delays.