DNS-DOMAIN NAME SYSTEM

The article that I am presenting is on the recent part that I came to know about DNS by our mentor at The Hacking School and I was amazed to hear the architecture of DNS(Domain Name System).

Let’s know, What is DNS?

The DNS provides mapping between human-readable names (like www.thehackingschool.com) and their associated IP addresses (like 35.200.150.126).

DNS can be best compared to a phone book where you look up the phone numbers listed by easier-to-remember names. DNS comes under the application layer protocol.

A user types www.thehackingschool.com in his browser, which then queries the DNS server for thehackingschool.com’s IP addresses. The servers return thehackingschool’s address so the browser can request data from thehackingschool’s web host, which returns the elements necessary to build their home page in the local browser.

Once your computer has the IP address for the domain name, your browser knows where to find it on the internet, your browser uses your computer to communicate with the server, where the domain name is hosted and requests for any associated files. The host server returns the files to computer which then its displayed on your browser.

What is a Root Server?

Root servers are DNS nameservers that operate in the root zone. These servers can directly answer queries for records stored or cached within the root zone, and they can also refer other requests to the appropriate Top Level Domain (TLD) server. The TLD servers are the DNS server group one step below root servers in the DNS hierarchy, and they are an integral part of resolving DNS queries.

Whenever a user enters a web address into their browser, this action triggers a DNS lookup, and all DNS lookups start at the root zone. Once the lookup hits the root zone, the lookup will then travel down the hierarchy of the DNS system, first hitting the TLDs servers, then the servers for specific domains (and possibly subdomains) until it finally hits the authoritative nameserver for the correct domain, which contains the numerical IP address of the website being sought. This IP address is then returned to the client. Interestingly, despite the number of steps required, this process can happen very quickly.

Root servers are an essential part of the infrastructure of the Internet; web browsers and many other internet tools would not work without them. There are 13 different IP addresses that serve the DNS root zone, and hundreds of redundant root servers exist around the globe to handle requests to the root zone.

Our ability to use domain names to quickly and easily retrieve the files or data from internet is entirely dependent on this tightly integrated communication.

I hope I was helpful in explaining about the DNS.