The Domain Name System (DNS) is a fundamental component of the internet that translates human-readable domain names into numerical IP addresses. Think of it as the internet’s phonebook. When you type a domain name like “what.edu.vn” into your web browser, DNS works behind the scenes to find the correct IP address associated with that name, allowing your browser to load the website. Every device connected to the internet is assigned a unique IP address, which is used for communication and location. DNS eliminates the need for users to memorize complex IP addresses, making the internet more accessible and user-friendly.
What is a DNS Server?
A DNS server is a specialized server that holds a database of domain names and their corresponding public IP addresses. Essentially, it acts as a translator between domain names and IP addresses. When you enter a domain name into your browser, your computer sends a request to a DNS server to look up the IP address for that domain. The DNS server then searches its database to find the matching IP address. Once found, it sends this IP address back to your computer. Your browser then uses this IP address to connect to the website’s hosting server and retrieve the website content. This entire process happens quickly and seamlessly in the background, enabling you to access websites effortlessly.
How Does DNS Work?
Resolving a domain name to its IP address typically involves a process that queries four different types of DNS servers working in conjunction. This multi-step process ensures efficiency and accuracy in finding the correct IP address. Here are the four servers involved in a standard DNS query:
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DNS Recursor (Resolver): The DNS recursor, also known as a DNS resolver, is the first server in the DNS query process. It receives your initial request from your DNS client (usually your operating system). The resolver then takes on the task of communicating with other DNS servers to find the IP address you’re looking for. It acts as an intermediary, querying the root, TLD, and authoritative nameservers on your behalf.
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Root Nameservers: Root nameservers are at the top of the DNS hierarchy. They are responsible for the DNS root zone of the internet. When a resolver queries a root nameserver, it responds by directing the resolver to the appropriate Top-Level Domain (TLD) nameserver based on the domain extension (like .com, .org, .edu) in your request.
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TLD Nameservers: A Top-Level Domain (TLD) nameserver stores information for all domain names within a specific top-level domain, such as .com or .org. When queried by the resolver, the TLD nameserver identifies the Authoritative Nameserver responsible for the specific domain name you requested and directs the resolver to it.
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Authoritative Nameservers: Authoritative nameservers are the final authority in the DNS query process. These servers hold the definitive DNS records for specific domain names. When the resolver queries the authoritative nameserver, it provides the actual IP address associated with the domain name. There are typically two types of authoritative nameservers:
- Primary (Master) Nameserver: This server holds the original, master copy of the DNS records for a domain.
- Secondary (Slave) Nameserver: This server holds a replica of the primary nameserver’s records. It serves as a backup and helps distribute the DNS query load, ensuring redundancy and availability.
