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DNS or Domain Name System makes up the very foundation of the internet, and something you use every day for basic internet functions. At the very basic level, think of DNS as the phonebook of the web. We find information online through domain names like wikihow.com or nba.com. We put these domain names on internet browsers, which interact through the Internet Protocol (IP) addresses. The job of DNS is to translate these domain names into IP for the web browser to load all the resources on the page.
DNS has a complete directory of domain names attached to their IP numbers. Computers use the numbers (IP addresses) to connect whereas us humans use the text-based domain names to access information. Back when the internet was small, it was easy to attach names with numbers and keep a tab of it. As more and more people are becoming online now, corresponding specific IP addresses is not to easy anymore. However, you can still enter an IP address to reach a specific website without adding domain text.
How does DNS Work?
Billions of internet users with more than 366.8 million domain names connect daily with the help of the DNS directory. The complete list of domain names and IP addresses lies somewhere on the internet, ready to help you out in a second. It all starts when you, the user, enters a domain name in the address bar of your browser. The browser sends a query to the internet to find a matching IP address for the name.
The query meets with a recursive resolver, a server that may be running under your internet service provider (ISP), phone carrier or third-party service. It is the job of the recursive resolver to look for the IP address on a DNS server. The query reaches a Root Server that knows the information of top-level domains with .com in them. Thousands of servers around the world support the root servers in finding the right information. DNS makes sure that your query is sent somewhere close to your physical location.
Then, a Top-Level Domain (TLD) is sought out, which holds information for second tier domains within the top-tier domains. TLD servers provides the name of the domain’s server which provides one piece of the puzzle. The recursive resolver then sends a query to the domain name server. The DNS server knows the complete address of the domain name and sends this information back to the recursive resolver.
Now the recursive resolver knows the IP address and sends it back to the web browser. The browser then sends a request to the website to load its content and show the website to you, the user.
Although we explained several steps of information access to you, but all of this happens under the blink of an eye! The time is kept short to serve the user as smoothly as possible. DNS is designed to keep efficiency in transactions over the internet. DNS servers are organized in a hierarchy to maintain this efficiency. It has been running for more than 30 years, so you may be taking it for granted. However, experts work round the clock to save the DNS servers from cyber miscreants.
Name Space Lookup
Popularly known as NsLookup, the tool is similar to the Unix/Linux command-line nslookup. For those who aren’t familiar with it, NsLookup queries specified domain name servers. After that, it retrieves the relevant records that have a connection with the provided domain name. Most of these records carry vital information like the internet protocol (IP) address of different domain names.
Here are some of the most useful DNS records:
- AAA – the IPv6 addresses of domains
- A – a domain’s IPv4 addresses
- MX: the server in charge of handling a domain’s email
- NS: the domain’s name server records
- CNAME: this contains the canonical name of the domain, which allows mapping between two domain names. In other words, multiple websites are able to refer to one web server.
- TXT: This record has information that could be used externally from a domain name server. name=value is what the content looks like. Authentication schemes like DKIM and SPF make use of this information.
In an era of cloud solutions, web-based programs, and remote teams, DNS is more crucial than it ever was. Businesses come to a halt when DNS doesn’t work. As such, a vital part of a network admin’s job is t monitor and trouble DNS on a regular basis.