DNS propagation definition
DNS propagation refers to the time it takes for all servers on the Internet to update the DNS records after a change has been made. These changes are usually not instant because they require implementation across a network of many servers. So the DNS propagation will not finish until every server updates the old DNS information.
A DNS propagation can take anywhere from a few hours to 72 hours to complete globally. Still, your domain name will not experience downtime if you adequately plan your DNS propagation. However, some users will get a cached version of your website until the DNS propagation completes across all servers.
Factors that affect DNS propagation time
- TTL or Time to Live: TTL refers to the time DNS information is allowed to exist (live) on a local or remote DNS server. For instance, if your DNS record has a TTL of 24 hours, all servers will continue to display the old information to end users for 24 hours, after which the servers will create a new DNS request to get the latest information.
- ISP or internet service provider: ISPs cache DNS records so that your site loads faster to end users worldwide. Some ISPs ignore TTL values and keep DNS records in the cache even after the TTL has expired, which can cause DNS propagation to take longer to complete.
- Domain name registry: When you change your domain’s authoritative name server, the changes affect the top-level domain (TLD) and root servers. And depending on their TTL, the DNS propagation can be prolonged further.