DOMAIN NAME

• A domain name serves as a unique identifier for a specific website on the internet.

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• It is typically a human-readable string of characters that represents a website's location.

What is a Domain Name?

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• Domain names follow a hierarchical structure, with levels separated by dots, such as "example.com" or "subdomain.example.com“.

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• Domain names are translated into corresponding IP addresses by Domain Name System (DNS) servers, allowing users to access websites using familiar names instead of numerical IP addresses.

Domain names are all managed by domain registries, which delegate the reservation of domain names to registrars. Anyone who wants to create a website can register a domain name with a registrar, and there are currently over 300 million registered domain names.

Who manages domain names?

A domain registrar is an internet company that manages your domain name, such as, example.com. Domain registrars use Domain Name System (DNS) records to connect your domain name with email, websites, and other web services. Popular domain registrars include GoDaddy, Squarespace, and IONOS

Structure of domain name

1. Subdomain (Optional): A subdomain is an optional component that precedes the main domain name and is separated by a dot. Subdomains can be used to organize and categorize content within a website. For example, in "subdomain.example.com", "subdomain" is the subdomain.

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• Domain Name: The domain name is the primary part of the web address and is typically the recognizable name of the website or organization. For instance, in "subdomain.example.com", "example" is the domain name.

3. Top-Level Domain (TLD): The top-level domain is the last part of the domain name and indicates the category or purpose of the website. Common TLDs include ".com", ".org", ".net", ".edu", ".gov", and country-code TLDs like ".uk", ".ca", ".jp", etc.

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4. Second-Level Domain (SLD): The second-level domain is the part of the domain name that comes before the top-level domain. It often represents the specific name or brand of the website or organization. In "subdomain.example.com", "example" is the second-level domain.

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5. Third-Level Domain: Similarly, additional levels of subdomains can be added before the second-level domain, forming a hierarchical structure.

• These are the most common types of TLDs and include extensions like:
• .com - Originally intended for commercial entities, now widely used for various purposes.
• .org - Initially intended for non-profit organizations but is also used by various entities.
• .net - Initially intended for network infrastructure organizations but now used more broadly.
• .info - Intended for informational websites.
• .biz - Intended for business or commercial use.
• .name - Intended for individuals' personal websites.
• .gov - Reserved for United States government entities.
• .edu - Reserved for educational institutions.

Generic Top-Level Domains (gTLDs):

• These TLDs are associated with specific countries or territories, and they include extensions like:
• .us - United States
• .uk - United Kingdom
• .de - Germany
• .cn - China
• .jp - Japan
• .au - Australia
• Each country or territory has its own rules and regulations for registering domains under its ccTLD.

Country Code Top-Level Domains (ccTLDs):

• These TLDs are specialized and sponsored by private organizations or communities, often with specific eligibility criteria for registration. Examples include:
• .gov - Government-sponsored domains in the United States.
• .edu - Education institutions in the United States.
• .aero - Aviation industry.
• .museum - Museums and related organizations.

Sponsored Top-Level Domains (sTLDs):

�Reverse domain, also known as reverse DNS (Domain Name System), refers to the process of mapping an IP address to a domain name. While DNS typically translates domain names to IP addresses, reverse DNS performs the opposite operation.

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Reverse DNS is an essential component of the internet infrastructure, providing a way to identify the domain names associated with specific IP addresses, which can be valuable for various network-related

tasks and security measures.

Reverse Domain Name

The Domain Name System (DNS) is a decentralized naming system for computers and other resources connected to the Internet or private networks. It translates human-readable domain names into numerical IP addresses, enabling users to access websites and services using easy-to-remember names instead of numerical addresses.

The Domain Name System (DNS) is a hierarchical decentralized naming system for computers, services, or any resource connected to the Internet or a private network.

Domain Name System (DNS)

1. Request Initiation: When a user enters a domain name (e.g., example.com) into a web browser, their device initiates a DNS query to find the corresponding IP address.

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• DNS Resolution: The query is sent to a DNS resolver (typically provided by the user's ISP or configured manually), which checks its cache for the requested domain's IP address. If the information isn't cached or has expired, the resolver proceeds with DNS resolution.

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Working Of DNS

3. Recursive Query: The resolver starts a recursive DNS query, reaching out to root DNS servers to locate the authoritative DNS server responsible for the top-level domain (e.g., .com).

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4. Iterative Queries: The resolver continues sending iterative queries to authoritative DNS servers, navigating down the DNS hierarchy until it reaches the authoritative server for the specific domain.

5. Response Retrieval: Once the authoritative server is found, it responds to the resolver with the IP address associated with the requested domain.

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6. Caching and Response: The resolver caches the IP address for future use and returns it to the user's device, allowing the browser to establish a connection with the desired web server.

FEATURES OF

DOMAIN NAME SYSTEM

1. Name Resolution: DNS translates human-readable domain names (e.g., example.com) into IP addresses (e.g., 192.0.2.1), facilitating communication between devices on the internet.

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• Hierarchical Structure: DNS is organized in a hierarchical structure, with domains arranged in levels, such as top-level domains (TLDs), second-level domains, and subdomains. This structure allows for efficient management and delegation of domains.

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3. Distributed Architecture: DNS operates on a distributed architecture, with multiple DNS servers distributed worldwide. This decentralization improves reliability, scalability, and fault tolerance.

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4. Caching: DNS resolvers cache DNS query results to reduce the time and resources required for subsequent queries. Caching improves performance by minimizing the need for repeated DNS resolutions.

5. Load Balancing: DNS can be used for load balancing by distributing traffic across multiple servers or data centers. By configuring DNS records with multiple IP addresses, traffic can be directed to different servers based on factors like geographic location or server health.

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6. Redundancy and Fault Tolerance: DNS supports redundancy and fault tolerance through mechanisms like DNS replication and secondary DNS servers. Redundant DNS servers ensure continued service availability even in the event of server failures or network issues.

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7. Security Features: DNS offers security features to protect against threats like DNS spoofing, cache poisoning, and denial-of-service (DDoS) attacks. Security extensions like DNSSEC (Domain Name System Security Extensions) provide cryptographic authentication and integrity verification of DNS data.

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8. Dynamic Updates: DNS supports dynamic updates, allowing DNS records to be updated automatically as network configurations change. This feature is essential for services like Dynamic Host Configuration Protocol (DHCP) and dynamic IP address assignment.

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9. Scalability: DNS is designed to scale efficiently to accommodate the growing size and complexity of the internet. The distributed nature of DNS and the use of caching help ensure scalability even as the number of domains and DNS queries increases.

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10. Global Reach: DNS operates globally, enabling seamless communication and access to internet resources from anywhere in the world. DNS servers are distributed across multiple continents, ensuring low latency and reliable connectivity for users worldwide.

Thank You

Presented by- Unnati Krishnauth

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