DNS Propagation is the time it takes for changes you make to your DNS to begin to take effect. Due to various levels of caching, changes you make to your DNS will most likely not take immediate effect. When a nameserver change is made on a domain it can take 4 to 24 hours for the DNS changes to propagate to all networks around the world. Your Internet Service Provider may also have caching periods that can delay the change from reflecting in your browser. This propagation will occur when you purchase a new domain, or change the DNS information for an existing domain (point the Nameservrs or change other DNS records).