DNS Propagation / Multi-Resolver Checker
After you change a DNS record, the new value doesn't reach everyone at once — different resolvers still serve the old answer until their cached copy (TTL) expires. This tool queries the same name from several major public resolvers side by side — Google (8.8.8.8), Cloudflare (1.1.1.1), Quad9 (9.9.9.9) and OpenDNS — and shows you each one's A, AAAA and NS answer together, so you can see at a glance whether a change has fully propagated or some resolvers are still lagging. It's also the fastest way to catch a GeoDNS / split-horizon setup that intentionally hands different IPs to different resolvers, or a genuinely inconsistent zone that's returning conflicting records.
Reviewed by the SysGlass team · Updated July 21, 2026
What it checks
- Queries the domain from multiple independent public resolvers (Google 8.8.8.8, Cloudflare 1.1.1.1, Quad9 9.9.9.9, OpenDNS) in parallel
- A records (IPv4) and AAAA records (IPv6) returned by each resolver, shown side by side
- NS records each resolver reports for the domain — useful right after a nameserver change or registrar transfer
- Whether every resolver agrees on the same answer, or some still serve a stale/different value
- A consolidated verdict: propagated (all resolvers consistent) vs still propagating / inconsistent
- The equivalent per-resolver dig commands (e.g. dig @8.8.8.8 example.com A) so you can reproduce each lookup
How to read the result
- All resolvers return the same record(s) → the change has propagated; what you see is what the world now sees.
- Some resolvers show the new value and others the old one → still propagating: the lagging resolvers are serving a cached answer and will update once the record's previous TTL expires (minutes to hours). Re-check shortly.
- Resolvers consistently disagree (and it's not just timing) → either a GeoDNS / split-horizon setup deliberately answering by location, or an inconsistent zone where your nameservers don't agree — investigate which is intended.
- Different NS answers across resolvers usually mean a nameserver change or transfer is mid-propagation at the registry/parent; give it time and confirm the parent delegation is correct.
- An empty answer from one resolver while others return data can indicate that resolver hasn't cached the name yet, or a filtering/blocking policy on that specific resolver.
- Because this queries public resolvers (not your authoritative servers directly), it reflects real-world cached state — for an authoritative, per-nameserver view of the zone itself, use the Nameserver & Zone Health check.
Frequently asked questions
How long does DNS propagation take?
It's governed by the TTL of the record's previous value, not a fixed clock. Resolvers cache an answer for up to its TTL, so a record that had a 3600-second (1-hour) TTL can take up to an hour to update everywhere, while a 300-second TTL clears in about five minutes. Lowering the TTL before a planned change makes the switch propagate faster. This tool shows you which resolvers have already picked up the new value so you don't have to guess.
Why do different resolvers return different IP addresses?
There are two common reasons. The first is timing — a change is mid-propagation and some resolvers still hold the old cached answer. The second is intentional: GeoDNS or split-horizon DNS deliberately returns different records depending on the resolver's location or network (for example, sending users to the nearest CDN edge). If the answers stay different long after any TTL would have expired, it's almost certainly by design rather than a propagation lag.
Which resolvers does it query?
Major, independent, globally-anycast public resolvers — Google Public DNS (8.8.8.8), Cloudflare (1.1.1.1), Quad9 (9.9.9.9) and OpenDNS — chosen because they're operated by different organisations on separate infrastructure. Agreement across all of them is a strong sign a change has propagated broadly; disagreement points to either caching lag or an intentional split answer.
Does this check my authoritative nameservers directly?
No — by design it queries public recursive resolvers to show the cached, real-world view that actual clients get. That's what you want when verifying propagation. To query each of your authoritative nameservers directly and confirm they all serve the same zone (matching SOA serial, consistent records), use the Nameserver & Zone Health tool instead; the two are complementary.
I updated a record but this still shows the old value — what should I do?
That's normal during the TTL window. Confirm the new record is correct at your DNS provider, then wait for the old TTL to elapse and re-run the check — the lagging resolvers will switch over. If only one resolver lags long after the TTL, it may simply not have re-queried yet. If every resolver still shows the old value well past the TTL, double-check you saved the change in the right zone and that your nameservers actually serve it.
Is the DNS propagation checker free?
Yes — it's a free public tool at sysglass.com/tools/dns-propagation with no sign-up. It performs read-only DNS lookups against public resolvers, and shows the equivalent dig @<resolver> commands so you can reproduce any result yourself.