How does the Domain Name System work?
Say you're scrolling through Google, and you click through to an interesting blog article. An awful lot of work goes on behind the scenes to make that connection, but the page loads in an instance. It's all thanks to the Domain Name System (DNS).
In reality the DNS is very complex, but here's the simplified version of what goes on in the microseconds after you click on a link.
Your internet connection (via BT, Virgin Media etc) provides Domain Name Resolvers; when you click through to a site these Resolvers then attempt to find its IP address, which is the virtual location of the files related to that site. They start by querying one of the world's 13 Root Nameservers for more information about the site location.
The Root Nameservers are vast databases, each run by different organisations, companies and universities which hold information on all of the world's TLDs (such as .com, .co.uk or .org). Many devices and Resolvers have built in information about which Root Nameserver to ask for each TLD, but if not then the Resolver will query each of the 13 Root Nameservers for more information about the location of the TLD you require, until it gains a proper response.
Note:If there is no TLD which matches your query (e.g. www.example.qq) then all 13 Root Nameservers will return an invalid response and you'll receive an error.
From there the Resolvers are directed to the TLD Nameservers. These don't store the exact details of the site, but instead will point your query to the relevant Hosting Nameservers which can provide this information. The website nameservers will look similar to these below:
When your query reaches the Hosting Nameservers, they respond with the exact IP details for your requested site. Your web browser then connects you to that IP address.
Note:A common issue that our support team see is where sites are pointed to the wrong Hosting Nameservers. In these cases the Hosting Nameservers fail to provide details about the site's IP and return an error.
That seems like a lot of processes for every link you click, but fortunately web browsers cut several corners by caching pages. For instance, when you land on www.example.com your web browser temporarily remembers the path to where that IP is located, meaning you can click through to www.example.com/test without having to make another Domain Name query.
That's the basics, if you've got any more questions about how this process works then feel free to leave us a question in the comments section below or ask us via @Twitter.