It can take up to 24 hours for a DNS change to propagate all over the world. For specific DNS records, the time it takes depends on the defined TTL value.
What is TTL?
TTL stands for “Time To Live”. The value is defined in seconds and tells a DNS server how long the record should be cached. A common value is 86400 seconds, which is 24 hours. When the TTL has expired, the DNS server will check if a change has been made. Although Websupports standard TTL is 600 seconds, which is 5 minutes.
Why can it take up to 24 hours for a DNS change to propagate?
DNS servers all over the world cache DNS records to be able to deliver an answer faster. How long the record is cached is defined by the TTL value.
My changes haven’t propagated even though it’s been 24 hours. How is that possible?
In some cases, it can take a little longer than 24 hours for a DNS change to take place. One example of this is if the TTL value is set at a higher value than 86400. Another cause can be that the device you’re checking from has cached the previous record locally. The local DNS cache can be emptied with Flushdns.
On a Windows PC you can clear the DNS cache with the following steps:
- Open the start/search menu and type “cmd”, then press enter to open the command console. In older versions of windows, you open the start menu and click “Run”, then you type “cmd” and press enter.
- Here you type “ipconfig / flushdns” and press “Enter”. If you get a message telling you the DNS cache has been cleared, you can try visiting the domain again in your browser.