Understanding DNS

Domain Name System (DNS) is the phone book of the internet. It keeps a directory of all the domain names and translates them into a language web browsers can understand. This language, known as an IP address, is a string of numeric characters that allows a client web browser (your browser) to communicate with a server (the server holding information you seek).

To understand DNS, it is important to understand a few basics.

Internet Protocol

Each device connected to the internet is assigned an address called an Internet Protocol, or IP address. This is a set of numeric digits that identifies users on the internet and also serves as a geographic address. An example is 192.68.1.1.

Domain Name

When you need information on the internet, you enter a website address like www.gesatech.com. The part of the address after “www” refers to the domain name. The “www,” short for World Wide Web, is just a CNAME in most cases, although it may also be used as a subdomain. Its usage emanated from a longstanding convention of naming internet hosts based on the web services they provide. The last segment (com) is the top level domain (TLD). Domain names make it easier for us to find websites on the internet. Imagine a world where you have to remember IP addresses for all your favourite websites.

How DNS Works

When you enter www.gesatech,com, you are requesting information to be published in your web browser. For your web browser to be able to fulfill your request, it has to first identify the location of the web server holding Gesatech’s information from among the millions of other servers already on the internet. The only way it can do so is by searching for its location from a pool of IP addresses. But because you entered a URL instead of the IP address, there has to be a resolution of the domain into a corresponding internet protocol that the web browser understands. DNS resolves this through a number of steps.

DNS Lookup

DNS lookup is a series of queries sent from your browser to other web servers to locate information on the internet. When there is no cached data in your browser, the DNS recursor sends a query to the root name server which begins the actual search for www.gesatech.com. To do this, the root name locates the exact TLD server. Because you are looking for gesatech.com, the root name server will request information from the .COM servers instead of .ORG. The information it needs is the authoritative name servers for gesatech.com. When it finds the authoritative name servers it will query them for the IP address of the server on which gesatech.com is located. Once this is found, the browser can now query the server to pull up the information you are looking for, if it is available. The information is then rendered in your browser as has been designed.

Cached Data

Whenever you visit a website, an abridged version of it is stored for a specific period in your web browser as cached data. Upon clicking go (or tapping enter) on your web browser the next time, a DNS recursor in your browser searches your cached data to see if there are results already there. If it finds said data, your browser renders quickly and you see results of your query. When there is nothing, the DNS recursor begins the DNS lookup described above.