DNS Propagation Checker
AvailableCheck whether a DNS change is visible everywhere: compare A, MX, TXT, NS and other records across public resolvers, with TTLs and response times.
Query
DNS resolvers
Global networks
Mostly anycast: one IP is served from many locations, so no single location is shown.
National & regional operators
Operator country is shown where a source states it; it is not the server’s verified location.
Servers with a listed region
Individual servers whose region is listed by the source.
No resolvers match your search.
Resolver list compiled from Public DNS list (mutin-sa, GitHub Gist) and Wirewiki — Public DNS servers. Locations are shown only where the source lists them; anycast resolvers have no single location.
Results
Enter a domain, choose resolvers and press Check DNS.
- Total
- 0
- Matching
- 0
- Different
- 0
- No records
- 0
- Errors
- 0
| Resolver | Location | Status | Records | TTL | Time |
|---|
No resolvers with this status.
How it works
The NetTools server sends the same query to each selected public resolver and compares the answers. Resolvers cache records for their TTL, so after a change some still return the old value until that time runs out — this is what “DNS propagation” usually means.
What “propagation” really is
DNS changes are not pushed around the internet. Your authoritative name servers answer with the new record immediately; what lags behind are resolver caches. Each recursive resolver (your ISP’s, Google’s, Cloudflare’s…) keeps an answer for as long as its TTL says. Until that time runs out, it keeps returning the old value — so different resolvers can disagree for up to one TTL.
- Plan ahead: lower the TTL (e.g. to 300 seconds) at least one old-TTL period before a change, then raise it again afterwards.
- Negative caching: a “does not exist” answer is cached too, for the zone’s negative TTL (from the SOA record).
- Name server changes also depend on the TTL of the NS records at the parent zone (TLD), which is often 1–2 days.
- Different but correct: CDNs and geo-DNS intentionally return different answers in different places, and filtering resolvers may block domains.
Safeguards & responsible use
- Only public domain names are accepted; internal names are rejected.
- Queries go only to the listed public resolvers, with per-client rate limits and timeouts.
Frequently asked questions
How long does DNS propagation take?
As long as the old record’s TTL. Resolvers that cached the previous answer keep it until the TTL expires; new lookups get the new answer immediately. Lowering the TTL a day before a planned change makes switches fast.
Why do resolvers show different answers?
Each resolver caches independently. Some still hold the old record, some use geo-dependent answers from CDNs, and filtering resolvers may block certain domains on purpose.
Why is a negative answer cached too?
If a name did not exist when it was looked up, resolvers cache that “NXDOMAIN” for the zone’s negative TTL (from the SOA record). Records created afterwards can appear missing until it expires.
Why doesn’t the tool show the exact city of each resolver?
Most large public resolvers use anycast: one IP address is served from many sites, and you reach the nearest. A location is only shown where the source data lists one.