How DNS propagation really works
Nothing is pushed around the world when you change a DNS record. The change is live on your domain's authoritative name servers (Cloudflare, your registrar or DNS host) within seconds. What takes time is caching: every resolver that looked the record up before your change keeps the old answer until its TTL (time to live) runs out, then asks again and gets the new one.
This tool asks your authoritative servers first, so you can see the new value is really published, then asks 18 public resolvers what they have cached. Resolvers still showing the old value will switch once the TTL shown next to them reaches zero.
Speeding up the next change
- A day before a planned move, lower the record's TTL to 300 seconds (5 minutes). Once old caches expire, the real change spreads in minutes.
- Changing name servers (NS) is slower: the parent zone (.com, .org…) caches NS records for up to 48 hours, and you can't shorten that.
- To see the change on your own computer straight away, flush its DNS cache (
ipconfig /flushdnson Windows,sudo resolvectl flush-cacheson Linux) or test withdig @1.1.1.1 example.com.
About the resolvers
Most large resolvers are anycast: one address served from many data centres. This check reaches each provider's site nearest to Cloudhim’s server, so it shows whether each provider has picked up the change, not every city. Answers that differ between providers are normal for up to one TTL after a change.