DNS Propagation, you have probably heard the term before but aren’t quite sure what it is. Don’t worry I get his question a lot so you are not alone. DNS Propagation is a complicated subject, and to fully understand it you need to know how the Internet works which includes many topics. In this blog I am going to give you an easy to comprehend overview over how the Internet works and DNS propagation.
Let’s start with DNS which stands for Domain Name Service. A domain name, such as “your-domain-name.com,” is an easy to remember name, which is associated to an IP (Internet Protocol) address such as 126.96.36.199. It’s much easier to remember google.com than 188.8.131.52 right, but the Internet works on IP addresses and just like a house that has a unique address every website is associated to a unique IP address. So when I open up my browser and go to google.com it’s really just going to 184.108.40.206. Why don’t you go ahead and try this out. In a new tab open up a new browser tab and type in http://220.127.116.11 and see where it takes you.
So now let’s move on to how your browser knows that google.com is associated to the IP address 18.104.22.168. This is the part where you need to understand more about how the Internet works. Your website lives on web server (which is just a beefed up computer setup to specifically run websites) in data center somewhere in the world and the web server will have one or several IP addresses used to find it.
In addition to these web servers there are also thousands of DNS servers located around the world. The sole responsibility of a DNS server is to take domains names and associate them to an IP address. These DNS servers store records for every domain and its IP address so that when you type google.com into your browser it will know to take you to 22.214.171.124 which is the address to the web server where your website is hosted .
So how does DNS Propagation fit into this? It’s quite simple actually. When DNS changes are made (like switching hosting providers or switching from an old website to a new one) every DNS server in the world needs to update its records of what IP is associated to a domains. You can imagine it takes some time for every DNS server in the world to update its records. So until they all update the to the new DNS / IP information one might have the old info while one might have the new info.
So let’s say we are launching a new site xyz.com on a different web server and we update the DNS records. Let’s also say that the DNS server I use has updated with the new information and I go to xyz.com and I see the new site but the DNS server you use hasn’t updated and you go to xyz.com and you see the old site. This is because the new DNS updates haven’t propagated to the DNS server you are using yet.
And that my friends is DNS propagation. It is simply just the time it takes for all the DNS servers around the world to update the new DNS updates. It’s also why all of us web nerds say it will take 1 – 24 hours for DNS propagation.
The Internet is pretty complex and can be difficult to understand how it works. Things like Root Servers, Caching, Authoritative Servers etc will make you say what language are you speaking? I hope this blog was able to take that Klingon language and make it easy to understand.