How this checker works
- Your browser asks five public resolvers at the same time: Cloudflare, Google, Control D, DNS.SB and CZ.NIC. Each is run by a different company and keeps its own cache.
- Each answer shows the records and how long that resolver will keep them cached. When answers differ, the longest cache time tells you when the last old copy runs out.
- Add the value you expect and each resolver is marked Updated or Old value, so you can see a change spread instead of guessing.
Why DNS changes take time to show
DNS doesn't push changes out. Every resolver that looked up your record keeps the answer for its TTL (time to live), set on the record itself, often an hour and sometimes a day. Until that runs out, it keeps giving the old answer, even though your DNS host already has the new one.
So "propagation" is really old copies expiring one by one. Five resolvers can't show every network: your internet provider and your own device keep caches too. If all five agree but you still see the old site, wait out the TTL or clear your device's DNS cache.
How to make your next DNS change faster
- A day or two before a planned move, lower the record's TTL to 300 seconds (5 minutes). Resolvers then keep the old answer for 5 minutes at most.
- Make the change, then check here until every resolver shows the new value.
- Once it has settled, raise the TTL again (3600 seconds is a common choice) so lookups stay fast.
How to check a resolver yourself
On macOS or Linux, run dig @1.1.1.1 yourbusiness.com A to ask Cloudflare, or dig @8.8.8.8 to ask Google. On Windows, use nslookup -type=A yourbusiness.com 1.1.1.1. To see what your DNS host itself answers, ask its name server: dig @ns1.yourhost.com yourbusiness.com A.