DNS Propagation Checker
Check DNS records across multiple global resolvers simultaneously. Verify propagation status after DNS changes. Includes...
Why DNS Changes Are Not Instant
DNS propagation delay occurs because recursive resolvers cache DNS answers based on the TTL (Time to Live) value set on each record. When you change a DNS record, resolvers that previously queried the old record continue serving the cached answer until the TTL expires. There is no central "push" mechanism — each resolver learns about changes independently when its cache expires and it queries the authoritative nameserver again.
The propagation checker queries multiple public resolvers simultaneously (Google 8.8.8.8, Cloudflare 1.1.1.1, Quad9 9.9.9.9, OpenDNS 208.67.222.222, and others) so you can see which resolvers still have the old record and which have the new one. If some resolvers show the new value and others show the old, the change is in progress — wait for all TTLs to expire.
Propagation Troubleshooting
Changes Visible on Some Resolvers Only
This is normal mid-propagation. Check the TTL on your record — if it was 3600 (1 hour) before the change, some resolvers cached it up to an hour ago. Wait for the oldest possible cache entry to expire.
Changes Not Visible After 48 Hours
Check that you changed the record on the authoritative nameserver, not a local copy. Verify NS records point to the correct nameservers. Some registrars cache zone data. Check that the zone serial number incremented.
Negative Caching (NXDOMAIN)
If a domain previously did not exist, resolvers cache the NXDOMAIN response for the SOA minimum TTL (often 86400 seconds = 24 hours). Adding a new record to a previously non-existent domain can take up to 24 hours to propagate.
4 Propagation Gotchas
CLI Equivalent
dig +short example.com @8.8.8.8 dig +short example.com @1.1.1.1 dig +short example.com @9.9.9.9 # Check authoritative directly: dig +short example.com @ns1.yourhost.com