At this point, we know that computers use numbers to communicate. Of course, we don’t know how to read it. In layman terms, DNS or the DOMAIN NAME SYSTEM converts these readable domains (e.g.: www.hostingspell.com) name to a form of numbers i.e. IP addresses (e.g.: 18.104.22.168).
We can call DNS a sort of ‘phone book’ that translates all the domain names you type into your browser to a machine-readable IP.
Thirty years ago, you would have to remember the IP address of the website to visit it. Thanks to the invention of DNS in the early 1980s, you don’t have to memorize IP addresses anymore.
This powerful tool is less known and understood. Knowing about DNS can actually be beneficial!
So, we got a basic idea of how the system works, by mapping IP address to domain names. But where is this information stored?
The nameservers store the records of DNS or the actual files that relate each domain name to its IP address.
These nameservers are distributed all around the globe and are known as root nameservers. The locations of the TLD (top-level domains) are stored instead of every domain.
TLDs are the two or three characters that end a domain name (e.g.: .com). Every TLD has their special set of nameservers that declares the authoritative for storing the DNS records for a particular domain. The authoritative nameservers are generally the DNS providers or DNS registrars.
So, the root servers aren’t the first step when you query a domain name. Your browser will ask your resolving nameserver if it has the DNS records for that domain.
When your computer wants to find the IP address of a domain name, it makes a request to a recursive DNS server or better known as a recursive resolver. A recursive resolver is a server that is generally operated and managed by ISP provider and it knows which DNS servers it needs to seek to resolve the name of a website and its IP address.
What is DNS propagation then?
DNS propagation is a simple concept. Every day loads of DNS changes are made (when someone switches hosting providers or switches from an old to a new website). This means that every DNS server around the world needs to update its records of the IP addresses associated with domains. One can imagine the time it takes for the servers around the globe to update their resources.
Let us consider a situation where we are launching a new website abcd.com on a different server and the DNS records are updated. On our side, the DNS server has been updated with the new information and the new website abcd.com is visible. On your side, the DNS server you use hasn’t updated and when you visit the new site you will still see the od site. This means the new DNS updates haven’t propagated yet to the DNS server you are currently using.
That’s it. DNS propagation is the time every DNS server takes to get updated with new DNS updates. When someone says it will take 20 hours for DNS propagation, you know they mean.
And that is a small guide on the DNS. The internet is a complicated place and it takes time to understand all its operations. But with time and some info intake, the internet gets easier.
Do check out our guide on CDN for a better understanding https://hostingspell.com/blog/how-to-set-up-and-disable-cloudflare-cdn/