DNS Propagation Checker
Changed a DNS record? See whether the world's biggest public DNS resolvers already return the new value, with the time left before each one refreshes. The same tool looks up every record of a domain, checks the SPF, DMARC and DKIM records that decide whether your email lands in the inbox, and finds the reverse DNS name of an IP address.
Free · No sign-up
How to use it
- Choose what to check: Propagation, All records, the SPF, DMARC and DKIM email records, or Reverse DNS.
- Enter a domain such as example.com (or an IP address for reverse DNS). For propagation, pick the record type, such as A, MX or TXT.
- Optionally enter the new value you expect. Each resolver is then marked green once it returns that value.
- Press Check. Turn on Check again every 30 seconds to watch a change spread without reloading.
Why use this tool
7 public resolvers
Google, Cloudflare, Quad9, AdGuard, NextDNS, DNS.SB and AliDNS are asked at the same time, side by side.
Time until refresh
Each answer shows its remaining TTL, so you know when a resolver will fetch the new value.
Expected value
Enter the new IP or host and see at a glance which resolvers already have it.
SPF lookup counter
Follows every include and counts DNS lookups against the limit of 10 that breaks many SPF records.
DMARC and DKIM
Explains your DMARC policy in plain words and finds DKIM keys under 20 common selectors, with key size.
Reverse DNS
Finds the PTR name of any IPv4 or IPv6 address and checks that it points back (forward-confirmed).
What is DNS propagation?
When you change a DNS record, the change is live on your DNS provider at once. But resolvers around the world (at ISPs, Google, Cloudflare and others) keep a cached copy of the old record until its TTL (time to live) runs out. "Propagation" is simply the time it takes for those caches to expire and fetch the new value.
So propagation time depends mostly on the TTL the record had before your change. A TTL of 300 means up to 5 minutes; 3600 means up to an hour; 86400 means up to a day. Name server (NS) changes at the registrar can take 24 to 48 hours because the TTL for the domain's delegation is set by the top-level domain.
| Record | What it does |
|---|---|
| A | Points a name to an IPv4 address |
| AAAA | Points a name to an IPv6 address |
| CNAME | Makes a name an alias of another name |
| MX | Mail servers that receive email for the domain |
| NS | Name servers that hold the domain's records |
| TXT | Text, used for SPF, DMARC and site verification |
| CAA | Certificate authorities allowed to issue SSL |
| SOA | Primary name server, serial and timers |
How this checker works
Your browser asks seven large public DNS resolvers directly over DNS-over-HTTPS and shows each answer with its remaining TTL and response time. These resolvers are anycast networks: each one answers from its location nearest to you, and together they serve a large share of the world's DNS traffic. When all of them return your new value, most visitors will see it too.
Your ISP's own resolver can still hold the old value until its TTL runs out. To see the change yourself sooner, flush your computer's DNS cache or switch to one of these public resolvers.
SPF, DKIM and DMARC in short
SPF lists the servers allowed to send email for your domain. DKIM adds a digital signature to every message, checked against a public key published in DNS. DMARC tells receivers what to do when a message fails both, and where to send reports. Since 2024, Gmail and Yahoo require all three from anyone sending email in bulk.
A good setup has exactly one SPF record that ends in ~all or -all and needs no more than 10 DNS lookups, a DKIM key of 2048 bits, and a DMARC record that moves from p=none to quarantine or reject once the reports show that all your real email passes.
Frequently asked questions
How long does DNS propagation take?
Usually minutes to a few hours, depending on the TTL the old record had. Name server changes can take up to 48 hours. Lower the TTL to 300 a day before a planned change to make it faster.
Why do resolvers show different values?
Some still have the old record cached. Each answer shows when that resolver will refresh. Different values can also be normal: big sites return different IP addresses depending on location and load.
How do I check my SPF record?
Choose SPF, DMARC, DKIM, enter your domain and press Check. It shows your SPF record, its policy (~all or -all), every include and how many of the 10 allowed DNS lookups it uses.
How do I find my DKIM selector?
Open an email you sent, view the original message or headers, and find DKIM-Signature. The selector is the value after s=. Common ones are google (Google Workspace) and selector1 or selector2 (Microsoft 365).
What is reverse DNS used for?
Reverse DNS maps an IP address back to a name. Mail servers check it, and many reject email from servers whose IP has no PTR record or one that doesn't point back to the same IP.
Can I see the change sooner on my own computer?
Yes. Flush the DNS cache (Windows: ipconfig /flushdns, macOS: sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder), restart your browser, or use a public resolver such as 1.1.1.1 or 8.8.8.8.
Is anything sent to your server?
No. Your browser asks the public DNS resolvers directly. We don't see or store the domains you check; only the last domain and tab are remembered in your browser.
How to change DNS records without downtime
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