// DNS CHECK
DNS propagation check
Asks several public resolvers the same question. When they agree, your DNS change has propagated.
What this measures
This check asks four public DNS resolvers — Google, Cloudflare, DNS.SB, and AdGuard — the same question about your domain and compares their answers with each other and with your domain's own authoritative nameserver, the source of truth. It shows whether a recent change has reached the resolvers yet, the TTL that bounds how long stragglers can lag, and flags common record misconfigurations.
How to read your result
- All resolvers agree
- Every resolver returns the same records. If they also match the authoritative nameserver, your change is fully visible — at least from these vantage points, which cover a large share of real-world lookups.
- Resolvers disagree
- Some resolvers still serve an old cached answer. This is normal mid-change: each resolver keeps the previous record until its cached copy's TTL runs out, so they update at different moments rather than all at once.
- The authoritative row
- The answer straight from your domain's own nameserver, bypassing every cache. If this row shows the new value but public resolvers do not, your change is correct and you are simply waiting for caches to expire. If this row shows the old value, the change never landed — waiting will not help.
- The TTL number
- Time To Live: how many seconds resolvers may cache this record. The largest TTL seen is your worst-case wait for full visibility — a 3600 TTL means any resolver that just cached the old value can serve it for up to an hour more.
- Warnings & notes
- Rule checks over the returned records: a CNAME at the bare domain (breaks the DNS spec), a single nameserver (single point of failure), multiple SPF records (receivers reject the policy entirely), or an informational note when no IPv6 (AAAA) record accompanies your IPv4.
Common causes & fixes
- Change not visible yet
- DNS "propagation" is not a broadcast — it is resolver caches expiring on the schedule your TTL set. Nothing pushes the new value out; each resolver just re-asks once its copy goes stale. If the authoritative row is correct, the only fix is waiting out the TTL.
- Changes always feel slow
- A high TTL (like 86400 — one day) makes every future change take up to a day to be seen everywhere. Before a planned migration, lower the TTL to 300 seconds, wait out the old TTL, then make the change — it will be visible in minutes.
- The source of truth is wrong
- If the authoritative nameserver itself returns the old value, you probably edited records at the wrong provider. Check which nameservers your registrar actually delegates to — records edited anywhere else are ignored.
- A flagged misconfiguration
- Fix warnings at your DNS provider: replace an apex CNAME with an A or ALIAS record, add a second nameserver, and merge multiple SPF records into one — the SPF standard allows exactly one, and extra records make mail receivers discard the policy.
Frequently asked questions
How long does DNS propagation take?
It is bounded by your record's TTL, not by a fixed clock. A 300-second TTL means most resolvers update within minutes; a one-day TTL means up to a day. The "up to 48 hours" figure you see quoted dates from an era of day-long default TTLs plus slow ISP resolvers — real changes with sensible TTLs are usually visible far sooner.
Can I speed up propagation?
Only in advance: lower the TTL before you make the change, then raise it again after. Once a change is made you cannot flush other people's resolver caches — you can only wait out the TTL that was on the old record.
Why do different resolvers show different answers?
Each resolver caches independently and re-queries on its own schedule. One that looked your domain up a second before your change will serve the old answer until its cached copy expires; one that never cached it returns the new answer immediately.
The resolvers agree but my site still shows the old server. Why?
Your own device and router cache DNS too, and browsers cache on top of that. Try a private window, another device, or flushing your local DNS cache — the public internet has likely already moved on.
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