What is DNS Propagation?

DNS propagation defines the process of updating information across the internet. There are two forms of DNS propagation: the first is the changes made to the DNS zone and the second is the changes made to WHOIS information.

A change made to your DNS zone will usually only affect a few servers and is the fastest change. Making a change that affects your WHOIS information can take up to 72 hours to propagate.

After the order of a domain or transfer of a domain, there will be a period where you can’t see your domain. This is due to millions of servers having to update with the new information. Your website may not be visible for up to 48 hours.

Or you can understand this way: -

When you make a change to your DNS records or update your domain(s) nameservers, you need to wait a certain amount of time before these changes are fully reflected across the internet.

This is because DNS records are cached by what's known as a DNS resolver. The job of a resolver is to help speed up browsing and reduce overall traffic by reducing the number of DNS lookups that are made to translate domain names to IP addresses. The time it takes for a resolver's cache to expire and a new lookup to be made is called DNS propagation.