Free DNS Propagation Checker

DNS propagation is the process by which updated DNS records spread across the global network of DNS resolvers. When you change a DNS record at your registrar or DNS provider, the update doesn't reach every resolver instantly. Instead, resolvers around the world gradually pick up the new record as their cached copies expire.

This delay exists because DNS is a distributed caching system. Each resolver independently caches records to reduce query load on authoritative servers and speed up responses for end users. The trade-off is that updates take time to reach every resolver.

When a DNS resolver receives a query, it first checks its local cache. If it has a valid (non-expired) cached record, it returns that immediately without contacting the authoritative server. If the cache is empty or the TTL has expired, the resolver performs a recursive lookup.

The recursive lookup process: 1. The resolver queries a root nameserver for the TLD 2. The root server refers to the TLD nameserver (e.g., .com) 3. The TLD server refers to your domain's authoritative nameserver 4. Your authoritative server returns the current record 5. The resolver caches the result for the duration of the TTL

This means that during propagation, some resolvers may still serve the old cached record while others have already fetched the new one.

• High TTL values — If your old record had a TTL of 86400 (24 hours), resolvers that cached it just before your change won't refresh for up to 24 hours.

• Negative caching — If a resolver queried your domain before the record existed, it may have cached a negative result (NXDOMAIN). Negative cache TTLs are set by the SOA record's minimum field.

• ISP resolver caching — Some ISP resolvers override TTLs with their own minimum values, typically 300-3600 seconds. This can extend propagation time beyond what your TTL suggests.

• CDN caching — If you're using a CDN, the CDN's own DNS layer may add additional caching. Check your CDN dashboard for DNS-level cache settings.

• Geo-DNS isn't propagation — A common false alarm: domains using Azure Traffic Manager, AWS Route 53 latency-based routing, or any geographic load balancer return *different IPs to different parts of the world by design*. Resolvers in Europe will see different answers than resolvers in the US, and both are correct simultaneously. The tool's `dispersion` field will read `geo_distributed` in this case — the zone is fully deployed, no change is in progress, and there is nothing to wait for. Flagging this as a propagation problem would send you on a wild goose chase.

• Local DNS cache — Your operating system and browser also cache DNS results. Flush your local cache (ipconfig /flushdns on Windows, sudo dscacheutil -flushcache on macOS) to see current resolver results.