By Debmedia Technologies LLP · Kolkata, India · Updated
What Is a DNS Checker?
A DNS checker is a tool that asks many DNS servers for the same record and shows you what each one answers. It is the quickest way to find out whether a change to your DNS has spread across the internet.
When you edit a record, only your DNS provider knows about it at first. Resolvers operated by internet providers and public services keep their own cached copy, so they update on their own schedule. This is called DNS propagation, and a DNS checker makes it visible.
How to Use This DNS Checker
- Type a domain name, such as example.com, into the box.
- Pick the record type you changed. A and AAAA hold IP addresses, MX holds mail servers, NS holds name servers and TXT holds text such as SPF.
- Optionally enter the value you expect, for example your new IP address.
- Press Check DNS and wait a few seconds for about 48 servers to answer.
You can also add one extra DNS server by IP address, which is handy for testing your own provider or office resolver.
Understanding the Results
Each row shows a provider, its location, the server address, a status and the answer it returned.
| Status | What it means |
|---|---|
| Resolved | The server returned the record, and it matches your expected value if you gave one. |
| Different value | The server returned a record, but not the value you expected. It may still hold the old one. |
| No record | The server answered but has no record of that type for the name. |
| Not found (NXDOMAIN) | The server says the name does not exist. |
| No response | The server did not answer within three seconds. Some public servers block or limit automated queries. |
The summary above the table counts how many servers agree. When every answering server returns the same record, your change has fully propagated.
Why DNS Answers Can Differ
If servers show different values, one of these is usually the cause:
- Caching. A resolver keeps an answer until the TTL runs out. A record with a TTL of 86400 seconds can stay cached for a full day.
- Geo or load-balanced DNS. Some services return different addresses depending on where the query comes from. That is intended behaviour, not a fault.
- A wrong or missing record. If no server returns your value after the TTL has passed, check the record at your provider.
- Name server changes. After moving to a new DNS host, make sure the NS records at your registrar point to it. The name server finder shows what is currently published.
Tips for Smooth DNS Changes
- Lower the TTL to 300 seconds a day before a planned change, then raise it again afterwards.
- Keep the old server running until the checker shows the new value everywhere.
- Test mail changes separately. Use the mail server lookup after editing MX records.
- Review the whole zone with the full record viewer when something looks wrong.
Our checker queries public resolvers from a single server, which is enough to see cache and propagation state. It cannot see what a private network or a personal device has cached. For the original standard behind these answers, read RFC 1035, the original DNS specification.
Frequently Asked Questions
Disclaimer: results come from live requests and can change as records and servers change. We cannot guarantee that every answer matches what every visitor sees.