What propagation means
Check the authoritative answer first: a correct new record there and an old recursive answer usually mean a cache is still serving its earlier TTL.
Authoritative nameservers publish a change first; recursive resolvers may retain an earlier positive or negative answer until its original TTL expires. There is no fixed worldwide completion time. Lowering the new TTL cannot shorten a copy already cached.
Compare authority with resolver caches
If the authoritative A answer has the new value but a recursive resolver has the previous one, record each TTL and query again after the old cached lifetime; another edit will not flush that cache.
- Confirm the registrar's nameservers for the domain. If you changed nameservers, check the old and new zones contain all required website and email records.
- Query an authoritative nameserver directly with
dig @ns1.example-dns.test www.example.com A, replacing both example names. - Query two recursive resolvers, for example your normal resolver and a public resolver, for the same name and record type. Note the returned value and remaining TTL.
Interpret the difference
If the authoritative answer is wrong, repair the record in the active zone. If it is correct but recursive answers vary, allow existing TTLs to run and test again. If all DNS answers are correct but the site or mail still fails, inspect the web service, TLS certificate, MX destination or local device cache; DNS is no longer the only suspect. CNAMEs, A and AAAA records can differ, so test the exact type used by the application.
Escalate with evidence
Send support the domain, expected and observed records, nameservers queried, time of each test and the affected service. Do not repeatedly flip records to chase a cached answer. Domain and DNS account owners control zone changes; Novasean can diagnose Novasean service targets, but cannot force independent recursive resolvers to expire their caches.
A worked cache timeline
At 09:00, a resolver caches an old A record for 3,600 seconds. At 09:05, the owner changes the authoritative A record and sets its new TTL to 300 seconds. That resolver can still answer with the old address until roughly 10:00 because it cached the previous answer before the change. A second resolver that had no cached answer may show the new address immediately. This difference is expected and does not prove the authoritative zone is inconsistent.
For a name that did not exist before, a resolver may cache the negative answer. Adding a new record with a short TTL cannot immediately clear that earlier negative cache. Nameserver changes also involve parent delegation caches, so check the registrar's delegation and both old and new authorities before assuming a website record itself is wrong.
Read the answer you receive
Use dig @ns1.provider.example www.example.com A +noall +answer for one authoritative nameserver and dig @1.1.1.1 www.example.com A +noall +answer for one recursive resolver. Replace example names and choose a resolver you trust. In an answer such as www.example.com. 240 IN A 192.0.2.10, 240 is the remaining TTL in seconds, A is the type and the last field is the illustrative address. A CNAME may lead to another name before the final A or AAAA answer. Check the entire chain.
| Pattern | Next action |
|---|---|
| All authoritative servers show wrong value | Correct the active zone. |
| Authorities disagree | Ask the DNS provider to check synchronisation or delegation. |
| Authority right, recursive resolver old | Wait for the old cache and retest; do not keep flipping the record. |
| SERVFAIL from validating resolvers | Check DNSSEC and nameserver health, including any registrar DS record. |
Common questions
Does clearing my browser cache speed DNS? It may change a local display but cannot expire a recursive resolver's cache. Test DNS directly first.
Why does IPv4 work while some visitors fail? An old AAAA record can send IPv6 clients elsewhere. Query A and AAAA separately.
Can Novasean set a universal completion time? No. The prior TTL, resolver behaviour, negative caching and delegation state determine what each client sees.
Does a smaller new TTL clear an old resolver cache? No. The old cached answer can remain until its earlier TTL expires.
Sources and technical references
Related guides
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