For those not in the know, the DNS, also known as “the Internet’s phone book,” is the system that translates domain names (the website URLs you type into your browser) into IP addresses (the domain names’ equivalent in a language that computers understand). You need to know that to understand DNS propagation. You also need to learn about other basic concepts related to it.

What Concepts Do You Need to Know to Understand DNS Propagation?

You’ve already taken the first step toward understanding DNS propagation—know what the DNS is. You also need to know these concepts:

  • DNS record: This is a file containing specific information about a domain, such as the IP address it resolves to, what email client it uses, and other information. There are several types of DNS records, each of which tells something important about the domain they belong to.
  • Nameserver: A DNS server that allows you to use a domain name instead of an IP address to access a website. It’s that part of the DNS that doesn’t require you to remember and type 142[.]250[.]176[.]14 each time you want to visit google[.]com.
  • Time-to-live (TTL) value: The amount of time a computer or network should keep data in its cache or memory before it gets discarded or revalidated.
  • A record: The DNS record that tells you what IP address your domain name resolves to.

What Is DNS Propagation?

DNS propagation is the time it takes a domain’s DNS information to get updated across the Internet after it is changed. Each time you modify data in any of your site’s DNS records, such as changing your nameserver, that change isn’t reflected all over the World Wide Web at once. As such, while people in the U.S., for instance, already feel the modification’s effect, those in the U.K. may not. Why? The closer a user is to your DNS server’s physical location, the faster they see or experience the change you made.

How Long Does It Take for DNS Propagation to Take Full Effect?

It can take between a few hours to three days for DNS propagation to take full effect—for all nameservers to reflect the change you made. The time frame depends on several factors, including your Internet service provider (ISP), registry, and DNS record TTL values.

The longer your ISP keeps data in its cache to speed up browsing and reduce traffic, the longer it takes to complete DNS propagation. While many registries can immediately reflect changes made to your nameserver settings, others may take days, making DNS propagation slower. Finally, the longer the TTL values you set, the more delayed DNS propagation is.

Can You Control the Length of DNS Propagation?

Sadly, the only factor in DNS propagation you can control is the TTL value. Every ISP and registry has policies and schedules for making DNS record updates.

So, while you can’t really control how long DNS propagation lasts, you can speed it up somewhat by following these best practices:

  • Modify your A record to point your hostname to the new destination IP address if you changed it.
  • Set a minimal TTL for the DNS record you modified. Some specialists recommend 5 minutes. Making it shorter may push many ISPs to ignore the TTL and retain the old record in their cache.

Can You Check the Progress of DNS Propagation?

Unfortunately, there is no foolproof way to check if DNS propagation has been completed because that would mean checking every DNS resolver and server in the world, or at least all those that serve your users.

—

While you can’t really speed up the DNS propagation process or know exactly when it’s completed each time you modify details in your DNS records, it is necessary. Without it, your site visitors will never experience the effects of the changes you made, which is unfortunate if you changed IP hosts, for instance, to improve your site speed and performance.