DNS propagation refers to a particular amount of time that is required for updating the DNS data (DNS records) in the entire global network of servers. These changes do not happen instantly because nameservers are designed to keep the DNS information in their cache memory for a specific time period defined by the TTL (Time-to-Live) values. Once it expires, the servers are able to check and refresh their data. For that reason, it is best if you plan well your DNS changes. That is going to minimize the chance for you to experience downtime. Find out additional information about DNS propagation!