What Is DNS Internet Server?


Larry Thompson

What Is DNS Internet Server?

The Domain Name System (DNS) is a critical component of the internet that translates human-readable domain names into IP addresses. It acts as a phonebook of the internet, allowing users to access websites and services using familiar domain names instead of remembering complex IP addresses.

How Does DNS Work?

When you type a domain name into your web browser, your computer sends a request to a DNS resolver (usually provided by your Internet Service Provider). The resolver then queries various DNS servers to find the IP address associated with that domain name.

The DNS system is hierarchical, with multiple levels of servers. The top-level servers are called root servers, followed by authoritative servers for top-level domains (TLDs) like .com or .org. Beneath the TLD servers are authoritative servers for individual domains.

Root Servers:

  • There are 13 sets of root servers distributed globally.
  • These servers store information about the top-level domain name servers.
  • They provide referrals to TLD servers for specific domain requests.

TLD Servers:

  • Each TLD has its own set of authoritative servers.
  • They store information about second-level domains and their corresponding authoritative name servers.
  • TLD server responses contain referrals to the authoritative name servers for specific domains.

Authoritative Name Servers:

  • These are the final level of DNS servers in the lookup process.
  • They store the actual IP addresses associated with specific domain names.
  • When a resolver queries an authoritative name server, it receives the IP address for the requested domain.

DNS Caching

To improve performance and reduce DNS lookup times, DNS resolvers and browsers cache previously resolved domain names and their corresponding IP addresses. This caching mechanism allows subsequent requests for the same domain to be resolved faster without querying the entire DNS hierarchy.

Browser Caching:

Browsers typically store DNS records for a certain period, known as the Time To Live (TTL). The TTL is defined by the authoritative name server for each domain. During this period, subsequent requests to the same domain are resolved using the cached IP address.

DNS Resolver Caching:

DNS resolvers also cache DNS records to minimize redundant queries. When a resolver receives a request for a specific domain, it first checks its cache. If a matching record is found within the TTL, it returns the cached IP address without querying other servers.

The Importance of DNS

The DNS system plays a crucial role in enabling users to access websites and services easily using memorable domain names. Without DNS, users would need to remember and enter complicated IP addresses manually. Additionally, DNS provides flexibility by allowing websites to change their hosting provider or IP address while keeping their domain name intact.

In conclusion,

The Domain Name System (DNS) is an essential infrastructure that translates human-readable domain names into IP addresses. It operates in a hierarchical manner with root servers, TLD servers, and authoritative name servers.

DNS caching at both browsers and resolvers helps improve performance by reducing lookup times. Understanding how DNS works is fundamental in grasping how the internet functions.

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