To know what a DNS Server is you must be familiar with the term DNS first.
DNS (Domain Name System) is basically a system which maps a domain name to an IP address. Now you might be wondering what is this domain name and IP address.
In simple terms, domain name is the web address you type to access a website like google.com.
But computer being a dumb machine doesn’t understand the domain name we typed. Instead, it uses IP address, a 32-bit number divided into 4 octets separated by decimals. The value of each octet can vary from 0 to 255. For example, IP address of google.com is 126.96.36.199.
It doesn’t matter if you enter the domain name or the IP address, the same site will open in both cases. But the problem with the IP address is that it is hard to remember. Since there are billions of IP addresses possible it becomes an impossible task to remember all of them. So for our convenience domain names were created.
The DNS matches the domain name with its corresponding IP address. And the DNS servers utilise this system for connecting us to different websites.
Whenever you enter the domain name into your browser, it first goes to the DNS server -where it is mapped to its corresponding IP.
You can imagine DNS server as the contact list in your smartphones. You store contact numbers of lots of people on your device along with their names.
Now if you want to call anyone, you don’t have to remember the number. You would just look up the name with which you saved the number and just dial it. It is quite easier to remember the name rather than the number.
You are saved from the cumbersome process of remembering all the numbers you saved.
Here the names in the contact list are the domains name and the contact numbers are the corresponding IPs.
Now that you know what a DNS server is it is the time that you understand the working of DNS server. In this process, your web browser acts as a client.
When you type the domain name into the browser your request first goes to local DNS servers which in turn sends our query to the root nameservers. There are total 13 root nameservers in the world.
Nameservers direct your query to TLD (Top Level Domain)nameservers. TLD servers analyse the TLD like .com, .org, .edu etc. Each of these TLDs has their own nameservers which receive respective TLD.
These TLD servers then send our query to authoritative nameservers, which stores information about specific domains in form of DNS records. These nameservers analyse the domain of the address like google, amazon etc.
The local DNS servers retrieve the data and establish the connection between the client (browser) and the requested site.
But since there are many steps in this process, the chances of a security breach in the DNS increases manifolds. Another threat to your DNS security could be DNS hijacking which redirects us to another malicious websites. Always use DNS protection programs to protect your system against DNS threats.
In spite of all these, most amazing thing here is that all these steps take just milliseconds! to complete.