Propagation DNS — Comment ça marche

DNS propagation is the process by which updated DNS records spread across all DNS servers worldwide. When you change your domain's DNS records, the change doesn't take effect instantly. It must propagate through the hierarchical DNS infrastructure. This typically takes 24-48 hours, but can range from minutes to 72 hours.

DNS uses caching to reduce query load. When a resolver looks up a domain, it stores the result based on TTL. Cache layers include: Browser cache (60 seconds default), OS cache, ISP resolver cache, and Public DNS cache (Google 8.8.8.8, Cloudflare 1.1.1.1).

Lower your TTL before making changes:

1. 72 hours before, lower TTL to 300 seconds (5 minutes)
2. Wait for old TTL to expire
3. Make your DNS change — propagates within ~5 minutes
4. Raise TTL back to 3600+

Use the DNS Visor Propagation Checker to monitor how your DNS changes spread across global DNS servers. The tool queries multiple servers in different locations and shows which have updated records.