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What is DNS Server?

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DNS server or Domain Name System is a directory of public IP (internet protocol) addresses and their affiliated host names. Often, DNS servers translate or resolve host names to IP addresses when requested. DNS servers operate exclusive software and connect using restricted protocols. 

How does DNS Work?

DNS operates by transforming a hostname into an IP address to make it more computer-friendly. Here is a DNS example. You type a domain name on your browser to access a specific website instead of an IP address.

An example of a domain name can be www.google.com. The domain name is changed to an IP address that is assigned to a gadget on the internet. This change is a DNS example query, an essential part of devices linking together to communicate through the internet. Let us discuss the types of DNS servers to understand DNS server meaning better. 

DNS Server

Types of DNS server

All DNS explained servers are classified into one of the following groups.

  • Recursive resolvers
  • Root nameservers
  • TLD name servers, and 
  • Authoritative nameservers

These DNS servers collaborate to convey a specific domain’s IP address to a client. Often, a client is a stub resolver (a straightforward resolver developed to form an operating system) 

Understanding a DNS Recursive Resolver

A recursive resolver is also known as a DNS recursor, and it forms the beginning of a DNS query. It acts as a mediator between a DNS nameserver and a client.

Once the web client sends a DNS query, the recursive resolver can either discharge a request to the root name server, or answer with cached data. It then sends another request to the TLD name server before generating the final requisition to an authoritative DNS explained name server.

After obtaining the required IP address from an authoritative name server, the recursive resolver transmits a response to the client. Amid this procedure, the recursive resolver caches data received from an authoritative name server.

If a client demands a domain IP address that another client had recently requested, the resolver will not have to communicate with the name servers. Instead, it will deliver the requested data from its cache. While there are many recursive resolver options available, many internet users opt for what their internet service provider supplies.  

DNS Root Nameserver

Root nameservers are DNS servers that work in the root zone. They provide direct answers for records within the root zone, and respond to various requests by listing authoritative name servers for the ideal TLD (top-level domain). Root nameservers are a crucial part of the internet infrastructure since they translate hostnames into IP addresses that ease the connection between internet hosts. 

TLD (Top-level Domain) Nameserver

A TLD nameserver controls data for domain names that share a domain extension such as .net and .com. A .com TLD nameserver, for instance, has data for each .com website.

When an internet user searches for google.com, for example, the root nameserver will respond. After that, the recursive resolver will discharge a query to a .com TLD nameserver that will then answer by directing to an authoritative nameserver. The Internet Assigned Numbers Authority (IANA) regulates TLD nameservers. The organization divides the TLD servers into two categories, as seen below. 

  • Country Code TLDs

These include state or country-specific domains such as .uk, .ru, and .us. 

  • Generic TLDs

These include non-country specific domains such as .com, .net, .org, .gov, and .edu. 

It is worth mentioning that there is a third group of infrastructure domain that is not used often. It was developed for the .arpa domain, an interim domain used in the development of present-day DNS. 

Authoritative Nameserver

When a TLD nameserver responds to the recursive resolver, the response guides it (the resolver) to an authoritative nameserver. Often, an authoritative nameserver is the final step in the course of an IP address.

An authoritative nameserver comprises data clear-cut to the domain name it presents. It can offer a recursive resolver with the specific server IP address available in the DNS A(address) record. Assuming the domain bears a CNAME record or alias, it will give the recursive resolver an alias domain.

The recursive resolver will then execute a full new DNS lookup to obtain records from the authoritative nameserver. Usually, this record is an A record comprising an IP address. 

DNS Reflection Attacks

DNS server meaning reflection attacks can overwhelm internet users with numerous alerts from DNS resolver servers. Attackers demand DNS records from any open DNS resolvers. They do this with the internet user’s parody IP address. Once the resolvers respond, the user receives unrequested DNS data that overpowers their machines. 

DNS Troubleshooting

If your browser cannot institute an internet connection, the Windows troubleshooting option often generates an error alert. This alert can either be “Your computer appears to be configured correctly, but the device or resource (DNS server) is not responding”, or “DNS server not responding”.

The core of such alerts can be tracked down to server outage, meaning that the DNS server is unavailable for a limited time. Often, internet users can troubleshoot these problems by restarting the router, changing or deactivating firewall settings, changing your browser, or choosing a different DNS server.

While the internet provider’s DNS server address is usually used automatically, the server can be easily overloaded and slow. Switching an internet provider DNS server with your preferred server is a simple task. You can even opt to use a public DNS server. All you need is lookup specific DNS server directory. 

What are the steps in a DNS lookup?

Often, DNS is associated with getting a domain name translated into a suitable IP address. To understand how this process operates, you would need to pursue a DNS lookup as it moves from a browser and navigates the DNS lookup process before getting back. 

Remember, many times, DNS lookup data is cached either remotely within the DNS infrastructure or locally within the querying computer. A DNS lookup comprises various steps. Once DNS data is cached, steps from the DNS lookup process are missed, and this accelerates the process. Read on to understand the steps in a DNS lookup. 

Requesting Website Data

An internet user gains access to a website by typing its domain name on their browser. The query navigates through the internet, where the DNS recursive resolver secures it. Your computer searches the IP address linked with your desired domain name from its local DNS cache.

The DNS cache stores DNS data that your computer has saved recently. If it is locally present, your preferred website is displayed. If there is no stored data in your computer, it will execute a DNS query to restore the correct data. 

Contact Recursive DNS Servers

If the data is in the local DNS cache in your computer, it will query recursive DNS servers from your internet service provider. Recursive DNS servers come with local DNS cache. Seeing that many of the internet service provider consumers use the same recursive DNS servers, chances are that common domain is cached, the DNS query ends in this step, and the user can view the website. 

Query Authoritative DNS Servers

What happens if recursive DNS servers do not have the data stored in their cache memory? The DNS query proceeds to the authoritative DNS server bearing information for a specific domain. Authoritative nameservers help with DNS record storage for their particular domain names.  

Obtain the DNS Record

To establish the IP address for www.google.com, internet users query the authoritative nameserver for the A record address record. A recursive DNS server obtains the address record for www.google.com from the authoritative nameserver. It then keeps the information in its local DNS cache.

If ensuing DNS queries demand the address record for www.goole.com, the recursive server will have the answer ready. This idea will help eliminate the need to repeat the DNS lookup process. All DNS records come with a time-to-live limit that indicates when a DNS record is due for expiry. Once the time lapses, the recursive DNS server requests an amended copy of the DNS data.  

Last DNS Step

The recursive DNS server holds the data and restores the A record to a user’s computer. Your computer will keep the DNS data in its local DNS cache, scan the DNS record for the IP address, and transfer the information to your browser. The browser will link the web server linked with the A records IP and the demonstration website.  

What is a DNS resolver?

A DNS resolver marks the beginning of a DNS lookup process. It helps handle the client that presented the first request. The resolver begins the series of queries that end in a URL getting translated into the ideal IP address. Remember, a regular uncached DNS lookup involves both iterative and recursive queries.

Knowing the difference between a recursive DNS resolver and a recursive DNS query is critical. The query defines the request presented to a DNS resolver, and demands an answer. A DNS recursive resolver is the computer that obtains a recursive query and prepares the response by applying the essential requests. 

You can Solve DNS Problems

DNS problems can interrupt your browsing experience. However, you can use the steps discussed here to solve them with ease. You can also contact a professional to help you solve persistent DNS problems.