Internet and Businesses Online

DNS: A guide to understand the domain name service and its mechanism

Introduction:

DNS is an acronym for Domain Name Servers, which are computers on the internet that store and forward domain names. Internet protocol addresses (IP addresses) are numerical addresses because they allow users to communicate over the internet or a network. As long as you’ve established your Domain name server properly, it’ll prompt you for a domain name and provide you with an IP address. If you go to “Start,” then “Run,” and type “cmd,” you’ll be able to do that.

Even though we use it on a daily basis, most of us aren’t aware of it. Even seasoned IT professionals don’t know everything there is to know about DNS, despite the fact that it is their job to ensure everything works properly. DNS is used by 99 percent of the people on the Internet without them even acknowledging it.

Every time you visit a website, you perform a DNS lookup in order to locate the site’s physical location. To find the email account for a domain, your ISP’s mail server performs a DNS lookup every moment you send an email. Because DNS is decentralised, no single server is responsible for maintaining all of the domain’s records.

It is extremely difficult to remember the IP addresses of all the internet sites we visit on a daily basis because it’s difficult to remember sequence of numbers. However, we are able to retain the meaning of words. In this case, the role of domain names is to be played. If you want to access a specific website, you’ll need its IP address as well as its URL. The mappings between IP addresses and names are provided by the DNS.

How DNS Works ?

It’s not difficult to understand how DNS works. When a user clicks on a link or bookmark, he or she enters a URL or the full URL. The browser asks for your domain’s IP address. When a user’s computer connects to a DNS server that has been set up on their computer, they are essentially accessing the servers of their internet service provider. DNS queries for this domain are routed through the provider’s server to the appropriate DNS server. Finally, the website’s DNS server responds with the correct URL.

Any central authority can’t make an address change because of the nature of the DNS system. A website owner’s Internet service provider’s servers can be used to manage DNS on his or her own servers. In the event that all of his servers are unavailable, his website will be unavailable as well. The risks are too great not to take the necessary precautionary measures so that DNS is always available online and up to date.

An IP address is a set of numbers that uniquely identifies a device on the Internet. It’s a little like having an address that directs you to a specific house. This IP address consists of four parts, each of which can contain any number between 0 and 255. As a result, an IP address is comprised of four digits ranging from 0-255:0-255:0-255.

After entering a URL, the browser first queries the DNS server for a matching IP address, and then connects to a server that has that IP address. Since this DNS server has to match so many websites and IP addresses, it is no longer a single server. Rather, it’s a network of systems spread across the globe, just like the Internet. As a result, in order to find a match, your browser must search through hundreds of millions of addresses.

There are many components to consider when it comes to understanding how a DNS setup works, so let’s look at some of them first.

What are the various components of DNS?

DNS consists of two components:

  • Nameserver
  • Resolver

Nameserver:

The nameserver performs the task of retrieving the names from the database. A single nameserver typically serves a group of machines. To get the requested information, the nameserver will use another nameserver. The ability to communicate with other servers does not need to be known by all servers. To get the location of all authoritative nameservers for all second-level domains, each nameserver must be able to contact the root nameserver

Resolver:

The Resolver is a client-side application that performs DNS lookups. A list of nameservers to use is provided. Name resolution is the job of each of these nameservers, as we learned earlier. Primary, Secondary, and Caching Nameservers are all types of Name Servers. The secondary nameservers are set up as a safety net in case of a primary nameserver failure.

No DNS database files are kept by caching nameservers; they only respond to name queries. Note that any change in the primary nameservers must also be propagated to secondary nameservers. This is because the database records belong to the primary nameservers. A “zone transfer” is used to spread the changes.

How does DNS Look-up work?

A DNS lookup entails asking a DNS server for the location of a specific DNS record. Using a DNS lookup, computers, servers, and smartphones can all have their email addresses and domain names converted to numerical addresses.

Here’s how a DNS Lookup process works:

  1. As soon as a user enters a web address, the computer transmits that information to the recursive DNS resolver.
  2. Your computer’s cache files are searched for an IP address by the recursive DNS resolver.
  3. Recursive DNS resolvers look for a DNS server, and if none are found, they try another.
  4. Searching for an IP address on one of the servers will end when recursive DNS resolvers find it on one of them.
  5. Other than this scenario, it is possible for the recursive DNS resolver to send requests to servers until it gets to authoritative DNS servers.
  6. As a final step, authoritative DNS servers search their databases for the IP address.
  7. The authoritative DNS servers will send the IP address back to the recursive DNS resolver once they’ve found the IP address.
  8. Recursive DNS resolvers send the IP address to your computer, and the website will open in your browser. 

The Importance of Reliable DNS Servers

Good DNS server matter because they either speed up you’re browsing or completely derail it. Websites may not be accessible if a DNS server is out of date or otherwise malfunctioning.

A fast or slow connection to a website can be attributed to the performance of a DNS server. Cloudflare is recommended by Run Cloud if you’re looking for a DNS server. In addition, Cloudflare’s Fast, Secure, and Resilient DNS is completely free to get started with.

What are the various kinds of attacks on DNS?

To affect DNS servers, attackers must use methods such as denial of service attacks or data corruption in order to gain access to the DNS infrastructure. DNS can be used in a variety of ways by hackers to infiltrate a network or system. Look at a few examples of this kind of attack.

Resource exhaustion

The hacker registers a domain and designates the target’s name server as the authoritative server for his domain in this type of DDoS attack. The hacker then uses a botnet to flood the recursive servers in that ISP’s network with requests. To avoid overloading, the DNS resolves queries for subdomains that don’t exist until the DNS infrastructure fails due to heavy traffic. Consequently, users are unable to use the internet. Using a DDoS solution can help prevent this kind of attack.

Related :  DDOS Attack-Types And Ways To React To Them ?

DNS hijacking

When a hacker performs this type of attack, the computer’s TCP/IP settings are overridden and the computer is directed to a rogue DNS server that the hacker controls. If a compromised computer makes a DNS request, the hacker’s DNS resolver handles the request. With this ability, hackers can infect your computer with malware or serve up advertisements. The majority of the time, this type of attack targets home routers

Unauthorized DNS tunneling

For the purpose of sending and receiving DNS queries, DNS tunneling creates a secure tunnel. This is especially useful for sending sensitive data over public networks. Virtual point-to-point connections are created between an authoritative server and a client in these tunnels, and traffic can flow through this virtual interface. When it comes to unauthorised data encoded in DNS packets, DNS is extremely vulnerable because of its widespread use. This makes it nearly impossible for firewalls to detect.

Reflection attacks

As part of a reflection attack, the hacker can flood the client machine with unrequested data via the DNS recursor. A system’s resources can be depleted if it becomes overburdened with data.

Read more : The Advantages Of An E-Commerce Website For Your Company

Conclusion:

People are helped in many different ways by DNS, such as being able to find the content they are looking for. DNS also eliminates need for users to remember the IP address, as each website in the modern era has a unique domain name, to which a unique IP address is assigned. Therefore, it is of great assistance in identifying the computer’s resources and services by the names of the domains under which they are hosted. For any queries related to DNS configuration please do contact us at Infinitive Host.

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