A DNS propagation checker shows what several public DNS resolvers currently answer for a domain, so you can tell whether a DNS change has spread. Most changes appear within minutes, but resolvers keep cached answers until the record’s TTL expires, and nameserver changes at the registry can take 24 to 48 hours.
What do the DNS record types mean?
| Record | What it does |
|---|---|
A | Points a name to an IPv4 address, for example the server that hosts your website. |
AAAA | Points a name to an IPv6 address. |
CNAME | Makes one name an alias of another name, such as www pointing to the main domain. |
MX | Lists the mail servers that receive email for the domain, with priorities. |
TXT | Holds free-form text, used for SPF, DKIM, DMARC and domain verification. |
NS | Names the authoritative nameservers for the domain. |
SOA | Start of authority: the primary nameserver, admin contact and zone timers. |
CAA | Says which certificate authorities may issue SSL certificates for the domain. |
SRV | Locates a specific service by host and port, for example SIP or Minecraft. |
PTR | Reverse lookup: maps an IP address back to a hostname. |
Why do different resolvers show different answers?
Every resolver caches records on its own schedule. After you change a record, a resolver that cached the old value keeps serving it until its TTL (time to live, in seconds) runs out, while a resolver that had not cached it fetches the new value straight away. Large providers also run many servers behind one address, so two queries a moment apart can briefly differ.
When every resolver returns the same answer, your change has propagated.
How can I make a DNS change propagate faster?
- Lower the TTL of the record to 300 seconds at least one full old-TTL period before you make the change.
- Make the change, then run the checker until every resolver agrees. Watch mode does this for you.
- Raise the TTL again afterwards, for example to 3600 seconds, to reduce lookups.
- Nameserver (NS) changes cannot be sped up this way, because they depend on the TTL set by the registry, often 24 to 48 hours.
How does this tool query DNS?
Your browser sends encrypted DNS-over-HTTPS queries (RFC 8484) directly to Google Public DNS, Cloudflare, DNS.SB, Control D, CZ.NIC, IIJ and AliDNS. Because the requests come from your own device, you see the answers and response times your network sees. Nothing is stored on our servers.