DNS propagation checker

Changed your DNS (moved your website, set up new email, added a verification record)? Type the domain and press Check. FernTool asks your domain’s own name server for the new answer, then asks 8 of the biggest public DNS services what they’re still showing, and tells you how long any old copies will last.

A = website address (IPv4) · AAAA = IPv6 · CNAME = alias (e.g. www) · MX = email · TXT = verification/SPF · NS = name servers

What “DNS propagation” really means

Nothing is actually pushed around the internet. When you change a record, only your DNS host has the new value straight away. Every other DNS resolver (Google, Cloudflare, your ISP’s, your router) keeps the old answer it fetched earlier until that copy expires. How long that is depends on the record’s TTL (time to live), set in seconds. A TTL of 3600 means up to an hour; 86400 means up to a day. “Propagation” is simply all those caches running out.

How to read the results

✓ up to date: that resolver gives the same answer as your domain’s own name server, so its users see the change.
✓ same network: a different address owned by the same network as the real answer. Big sites (Google, GitHub, CDNs) do this deliberately, so it counts as up to date.
✗ old / different: it still has an older copy. The “cached for” column shows roughly how long until it asks again.
Name server row: this is the source of truth. If it still shows the old value, the change wasn’t saved, or you edited DNS at the wrong company. Run a WHOIS lookup to see which name servers your domain really uses.

Honest limits of any propagation checker

Big public resolvers such as 1.1.1.1 and 8.8.8.8 run in hundreds of cities, and each location has its own cache. We see the copy at the location nearest our server, so a different city may update a little earlier or later. ISP resolvers (Telkom, Vodacom, MTN, Afrihost and others) only answer their own customers, so no website can check them from outside. Sites that show a world map of “propagation” are querying a list of small servers with the same limits. When our check is all green but you still see the old site, the old copy is on your side: flush your DNS cache or try mobile data.

Moving a website or email? Do it in this order

A day before, lower the TTL of the records you’ll change to 300 seconds (5 minutes).
Make the change at your DNS host, then check here until every row is green.
Keep the old server running until then, so nobody lands on a dead site or loses email.
Raise the TTL again (e.g. 3600) once everything works.

Frequently asked questions

How long does DNS propagation take?

Usually minutes to a few hours. Each resolver keeps the old answer until its TTL (time to live) runs out, so the wait is at most the TTL the record had before you changed it. Name server changes at the registry can take up to 24 to 48 hours.

Why do I still see the old website when the checker says it’s updated?

Your own computer, browser or router can still hold the old answer, and so can your ISP’s resolver. Flush your DNS cache, try another browser or mobile data, or wait for the TTL to run out.

Can I speed up DNS propagation?

Not after the change. Before a planned move, lower the record’s TTL (for example to 300 seconds) a day ahead, make the change, then raise it again once everything works.

What does “authoritative” mean?

The authoritative name server is the one that actually holds your domain’s records (often at your registrar, host or Cloudflare). Its answer is the truth; public resolvers just keep copies.

Why does one resolver show nothing or NXDOMAIN?

Either it cached a “doesn’t exist” answer from before the record was added (it clears when that cached answer expires), or the record really is missing. Check the authoritative row first.

Related tools and guides

API: GET /api/dns-propagation/{domain}?type=A · MCP tool check_dns_propagation. Resolvers: Cloudflare (1.1.1.1), Google (8.8.8.8), Cisco OpenDNS, AdGuard DNS, NextDNS, Control D, CleanBrowsing, AliDNS (Alibaba, China), plus your domain’s own name server.