NetKit

DNS propagation checker

Ask eight public resolvers for the same record at the same moment. See who already has your new value, who is still serving the old one, and how many seconds until they refresh.

Propagation
Try:

Results from Cloudflare, Google, Quad9, OpenDNS, AdGuard, Mullvad, DNS.SB and AliDNS appear here.

Propagation is just caches expiring

DNS has no mechanism for telling the world a record changed. Each recursive resolver stores the answer it received for as long as the record's TTL allows, then asks again. "Propagation" is the gradual expiry of those cached copies across millions of resolvers. That gives you a reliable playbook for migrations:

  1. A day or more before the change, lower the record's TTL to 300 seconds, and wait at least the old TTL.
  2. Make the change. Within about five minutes nearly every resolver has the new value.
  3. Check here that all resolvers agree, then raise the TTL again.

Changing name servers is different: the delegation lives in the TLD's zone (for .com, a 172,800-second TTL, i.e. 48 hours), which you can't lower. Keep the old DNS host serving identical records until the switch completes. Check the current delegation with a WHOIS lookup.

Questions people ask

How long does DNS propagation take?
There is no push; resolvers simply keep cached answers until the TTL expires. If the old record had a TTL of 3600, most resolvers pick up the change within an hour. Name server (NS) changes at the registrar can take up to 48 hours because TLD servers set long TTLs on delegations.
Why does one resolver still show the old value?
It cached the answer shortly before you changed it and is waiting out the TTL. The TTL column shows the seconds remaining in that resolver's cache, so you can read off exactly when it will refresh.
Can I force propagation?
Not globally. You can purge Cloudflare's cache (1.1.1.1/purge-cache) and Google's (developers.google.com/speed/public-dns/cache), flush your own machine (ipconfig /flushdns, sudo dscacheutil -flushcache), and lower the TTL in advance of the next change.
Why do resolvers return different IPs even without a change?
Large sites and CDNs use GeoDNS or anycast load balancing, returning addresses near the resolver. Different values are normal for them; compare against what your DNS host shows.