Samacheer Kalvi Class 12 Computer Applications Solutions Chapter 12 DNS (Domain Name System)

Part I

Choose The Correct Answers

 

Question 1. Which of the following is used to maintain all the directory of domain names?
(a) Domain name system
(b) Domain name space
(c) Name space
(d) IP address
Answer: (a) Domain name system
In simple words: The domain name system (DNS) works like a phone book for the internet, keeping track of all domain names and their matching IP addresses. This helps your computer find websites easily.

🎯 Exam Tip: Remember that DNS translates human-readable domain names (like google.com) into machine-readable IP addresses (like 172.217.160.142).

 

Question 2. Which of the following notation is used to denote IPv4 addresses?
(a) Binary
(b) Dotted-decimal
(c) Hexadecimal
(d) a and b
Answer: (d) a and b
In simple words: IPv4 addresses can be written as binary numbers (zeros and ones) or as dotted-decimal numbers (like 192.168.1.1). Both ways show the same address.

🎯 Exam Tip: While IPv4 addresses are often displayed in dotted-decimal for human readability, computers process them as binary. Both representations are valid.

 

Question 3. How many bits are used in the IPv addresses?
(a) 32
(b) 64
(c) 128
(d) 16
Answer: (c) 128
In simple words: IP addresses come in different versions. The new IPv6 addresses use 128 bits, which allows for many more unique addresses than the older IPv4 addresses.

🎯 Exam Tip: This question might be specifically referring to IPv6 addresses, as IPv4 uses 32 bits. Always clarify the IP version if it's not explicitly stated, or choose the most advanced/common option in a general context.

 

Question 4. Expansion of URL is
a) Domain name system
b) Universal Resource Location
c) Uniform Resource Locator
d) Universal Resource Locator
Answer: (c) Uniform Resource Locator
In simple words: URL is a short way to say "Uniform Resource Locator." It's the full address you type into your browser to visit a webpage or find something on the internet.

🎯 Exam Tip: Be careful with options that sound similar; "Uniform Resource Locator" is the correct full form for URL.

 

Question 5. How many types are available in Relative URL?
a) 2
b) 3
c) 4
d) 5
Answer: (a) 2
In simple words: There are two types of URLs: Absolute and Relative. A Relative URL is a shorter address that only works when you are already in a specific location on a website.

🎯 Exam Tip: Relative URLs are useful for linking within the same website because they only specify the path from the current page, making them shorter and easier to manage.

 

Question 6. Maximum characters used in the label of a node?
a) 255
b) 128
c) 63
d) 32
Answer: (c) 63
In simple words: Each small part of a domain name, called a label, can only have up to 63 characters. This helps keep domain names manageable.

🎯 Exam Tip: While individual labels can be 63 characters long, the total length of a full domain name (including dots) cannot exceed 255 characters.

 

Question 7. In domain name, sequence of labels are separated by
a) ;
b) .(dot)
d) NULL
Answer: (b) .(dot)
In simple words: Parts of a domain name, like "www", "google", and "com", are always separated by a dot (.). This dot acts like a divider between each label in the address.

🎯 Exam Tip: The dot acts as a hierarchical separator, indicating different levels of the domain name system.

 

Question 8. Pick the odd one out from the following.
a) node
b) label
c) domain
d) server
Answer: (d) server
In simple words: Node, label, and domain are all parts of how a domain name is structured. A server is a physical computer that stores and serves website content, which is different from the naming structure itself.

🎯 Exam Tip: Understand the difference between the logical structure of domain names (nodes, labels, domains) and the physical infrastructure (servers) that supports them.

 

Question 9. Which of the following initiates the mapping of the domain name to IP address?
a) Zone
b) Domain
c) Resolver
d) Name servers
Answer: (c) Resolver
In simple words: A resolver is a special program that starts the process of turning a website name (like example.com) into an IP address (like 192.0.2.1). It's the first step in finding a website online.

🎯 Exam Tip: The resolver acts as the client-side component, initiating the DNS query when you type a website address into your browser.

 

Question 10. Which is the contiguous area up to which the server has access?
a) Zone
b) Domain
c) Resolver
d) Name servers
Answer: (a) Zone
In simple words: A zone is a connected area in the domain name system where a specific server has control and information. It defines the limits of what a name server manages.

🎯 Exam Tip: A zone is an administrative space that a specific DNS server manages, and it can contain multiple domains or subdomains within its defined boundary.

 

Question 11. ISP stands for
a) International Service provider
b) Internet Service Provider
c) Internet service Protocol
d) Index service provider
Answer: (b) Internet Service Provider
In simple words: ISP is short for "Internet Service Provider." This is the company that gives you access to the internet, like your home internet company.

🎯 Exam Tip: Knowing common acronyms like ISP is important for understanding network and internet concepts.

 

Question 12. TLD stands for
a) Top Level Data
b) Top Logical Domain
c) Term Level Data
d) Top Level Domain
Answer: (d) Top Level Domain
In simple words: TLD means "Top Level Domain." This is the last part of a website address, like ".com", ".org", or ".net". It helps categorize websites.

🎯 Exam Tip: Top-level domains are crucial for organizing the internet and can indicate the purpose or geographical location of a website.

 

Question 13. Which of the following statements are true?
i) Domains name is a part of URL.
ii) URL made up of four parts
iii) The relative URL is a part of the Absolute URL
iv) URL doesn't contain any protocol
a) i & ii
c) i, ii & iii
d) i, ii & iv
Answer: (b) ii
In simple words: A URL usually has four main parts: the protocol (like http), the domain name (like example.com), the path (like /folder/page.html), and sometimes a port number. Statement (ii) correctly says that a URL is made up of four parts, which is generally true for its common structure.

🎯 Exam Tip: Understand the basic components of a URL (protocol, hostname, path, and sometimes query parameters or port) to correctly identify true statements about its structure.

 

Question 14. Assertion (A): The number of addresses used in the IPv6 addressing method is 128.
Reason (R): IPv6 address is a 128-bit unique address.
a) A is true and R is false.
b) A is false and R is true.
c) Both A and R are correct and R is the correct explanation of A.
d) Both A and R are correct and R is not the correct explanation of A
Answer: (b) A is false and R is true.
In simple words: The assertion is wrong because 128 is the number of bits in an IPv6 address, not the number of addresses used. The reason is correct because an IPv6 address indeed uses 128 bits and each address is unique.

🎯 Exam Tip: Distinguish carefully between the number of *bits* in an address (its length) and the total *number of addresses* that can be generated with that many bits (which is \(2^{number of bits}\)).

 

Question 15. Match the following
a. domain – 1. The progress that initiates translation
b. zone – 2. contains a database of domain names
c. name server 3. single node
d. resolver 4. contiguous nodes
a. 1432
b. 3421
c. 3214
d. 3412
Answer: (c) 3214
In simple words: A domain is a single node. A zone holds a database of domain names. A name server has a database of domain names. A resolver starts the translation process.

🎯 Exam Tip: Clearly understand the role of each component: a domain is a structural unit, a zone is an administrative area, a name server stores records, and a resolver initiates lookups.

Part II

Short Answers

 

Question 1. List any four domain names.
Answer: Here are four common domain names and their meanings:
1. com: Stands for Commercial Organization, used by businesses.
2. edu: Stands for Educational Institution, used by schools and universities.
3. gov: Stands for Government (US), used by government agencies in the United States.
4. mil: Stands for Military groups, used by military organizations.
In simple words: Four common website endings are .com for businesses, .edu for schools, .gov for government, and .mil for the military. These endings tell you what kind of website it is.

🎯 Exam Tip: Remember these top-level domains (TLDs) as they classify websites by their purpose or organization type.

 

Question 2. What is an IP address?
Answer: An Internet Protocol (IP) address is a unique number that identifies a device on a network. It acts like a logical address at the network layer. Just like a house number helps you find a specific home, an IP address helps find a specific computer or device connected to the internet. This system ensures every host system can be located and communicated with across the entire network.
In simple words: An IP address is a special number for your computer on the internet. It helps other computers find and talk to your computer, just like a house number helps mail reach your home.

🎯 Exam Tip: Emphasize that an IP address is a *logical* address, distinct from a physical MAC address, and is essential for devices to communicate on a network.

 

Question 3. What are the types of IP address?
Answer: There are two main types of IP addresses currently in use:
1. IPv4 Address
2. IPv6 Address
Each type uses a different format and number of bits to create addresses. IPv6 was developed to handle the growing number of devices connecting to the internet, as IPv4 addresses were running out.
In simple words: The two main kinds of IP addresses are IPv4 and IPv6. They are like different versions, with IPv6 being newer and having more addresses.

🎯 Exam Tip: Briefly state the two primary types of IP addresses and mention that IPv6 was created to solve the address exhaustion problem of IPv4.

 

Question 4. What is an URL?
Answer: A URL, which stands for Uniform Resource Locator, is the full address of a document or resource on the Internet. It is a complete web address used to find any online content. A URL is typically made up of four main parts: the protocol (like `http` or `https`), the hostname (which often includes the domain name like `www.example.com`), the folder name (if the resource is in a directory), and the file name (the specific page or file).
In simple words: A URL is a full web address that helps you find specific things like webpages or files on the internet. It includes different parts like the method, website name, and file location.

🎯 Exam Tip: When defining a URL, always mention its full form "Uniform Resource Locator" and briefly list its key components like protocol and domain name.

 

Question 5. List out four URLs you know.
Answer: Here are four examples of URLs:
1. `http://www.example.com/index.html`
2. `http://www.computer.com`
3. `http://www.ibm.com`
4. `https://www.hellotravel.com`
These examples show how protocols (http/https) and specific domain names are combined to create unique addresses for online resources.
In simple words: Some example website addresses are `http://www.example.com/index.html`, `http://www.computer.com`, `http://www.ibm.com`, and `https://www.hellotravel.com`.

🎯 Exam Tip: When providing URL examples, ensure they are well-formed and illustrate different domains or file paths.

 

Question 6. What are the types of URLs?
Answer: The URL is mainly divided into two types:
1. Absolute URL
2. Relative URL
An absolute URL provides the complete path to a resource, while a relative URL specifies the path in relation to the current document. These two types help in linking web resources differently based on context.
In simple words: There are two main kinds of URLs: Absolute URLs, which are full addresses, and Relative URLs, which are shorter addresses used for things within the same website.

🎯 Exam Tip: Clearly state the two types: Absolute and Relative URL. Briefly explain their core difference to show understanding.

 

Question 7. What is a domain?
Answer: A domain is a single node within the hierarchical Domain Name System (DNS) namespace. In the DNS tree structure, a domain acts as a sub-structure tree, which can be further divided into smaller subdomains. For instance, in `example.com`, `example` is a domain within the `.com` top-level domain. This organized structure helps manage vast numbers of internet resources.
In simple words: A domain is like a small section or a single point in the big online naming system. It's a part of a larger internet address that can also have smaller parts inside it.

🎯 Exam Tip: Define a domain as a node in the DNS namespace and mention its hierarchical nature, allowing for subdomains.

 

Question 8. What is a zone?
Answer: A zone is a connected area in the Domain Name System (DNS) that a specific server has access to and manages. It represents the contiguous part of the DNS namespace where a server is authorized to provide answers. If a zone has only one domain, then that zone and the domain are considered the same, meaning the server assigned to it does not divide it into further subdomains. This administrative division helps in distributing the management of DNS.
In simple words: A zone is a section of the internet's naming system that one server controls. If the zone has only one website name, then the zone and the website name are exactly the same thing to that server.

🎯 Exam Tip: Explain that a zone is an administrative unit within the DNS, defining the scope of authority for a particular DNS server. Highlight that a single-domain zone is essentially the domain itself.

 

Question 9. What is a resolver?
Answer: A resolver is a program or service that starts the process of converting a domain name into an IP address. When a host system needs to find the IP address for a domain name (or vice versa), it sends a query to the resolver. The resolver then carries out the necessary steps to translate the domain name and find the correct IP address. This is how your computer finds the server where a website is hosted.
In simple words: A resolver is a computer program that helps find the internet address (IP address) for a website name you type. It does the job of translating the name into numbers so your computer can connect.

🎯 Exam Tip: Focus on the resolver's primary role as the initiator of the DNS lookup process, translating domain names to IP addresses for host systems.

 

Question 10. What are the categories available in domain name space?
Answer: The Domain Name System (DNS) includes three main important components that work together to organize the domain name space. These are:
1. Namespace
2. Name server
3. Zone
These components collectively ensure that domain names can be managed, translated, and resolved efficiently across the internet, making it easy for users to access websites.
In simple words: The domain name space has three important parts: the Namespace (the whole system), Name servers (computers that store name information), and Zones (areas managed by those servers).

🎯 Exam Tip: List the three key components (Namespace, Name server, Zone) and briefly explain their collaborative function in the DNS.

 

Question 11. Write any four generic Top-Level Domain.
Answer: Here are four generic Top-Level Domains (gTLDs) and their meanings, which help categorize websites globally:

These domains are widely used and recognized across the internet, providing a clear indication of the website's primary purpose.
In simple words: Four common website endings are .com for businesses, .edu for schools, .gov for government, and .mil for the military.

🎯 Exam Tip: When listing gTLDs, provide both the domain name (e.g., .com) and its corresponding meaning for a complete answer.

Part III

Explain In Brief Answer

 

Question 1. Write a note on DNS.
Answer: The Domain Name System (DNS) is like the internet's phone book. It translates human-readable domain names (like `www.example.com`) into machine-readable IP addresses (like `192.0.2.1`). This system uses a hierarchical namespace, which is designed in a tree-like structure with a root element at the top. This tree can have up to 128 levels, starting from level 0 to level 127. The DNS is crucial for all internet communication, as it allows users to access websites using easy-to-remember names instead of complex numbers.
In simple words: DNS is like a phone book for the internet. It turns website names into number addresses so computers can find each other. It's built like a tree with many levels, helping everything stay organized.

🎯 Exam Tip: Start by defining DNS as the internet's phone book and its primary function of translating domain names to IP addresses. Mention its hierarchical structure for completeness.

 

Question 2. Differentiate IPv4 and IPv6.
Answer: Here are the key differences between IPv4 and IPv6, the two versions of the Internet Protocol used for addressing devices on a network:

IPv6 was developed to address the limitations of IPv4, especially the shortage of available IP addresses, and offers enhanced features like better security and efficiency.
In simple words: IPv4 uses 32 bits for addresses, while IPv6 uses 128 bits, meaning IPv6 has many more possible addresses. IPv4 often needs manual setup, but IPv6 can set up addresses by itself. IPv6 also offers better security and connection reliability.

🎯 Exam Tip: When differentiating, focus on the address length, address configuration methods, connection integrity, and the total address space for each protocol.

 

Question 3. Differentiate Domain name and URL
Answer: Here's a comparison between a URL and a Domain Name:

A URL is a complete path to a specific resource, while a domain name is just one part of that path, providing a human-readable identifier for a website or server. Thus, a domain name is a component of a URL.
In simple words: A URL is the full address of something on the internet, like a webpage, including all the details. A domain name is just one part of that URL, like "google.com", which is the easy-to-remember name for a website.

🎯 Exam Tip: Emphasize that a URL is a comprehensive address for a resource, whereas a domain name is a specific, human-friendly identifier that forms a part of the URL.

 

Question 4. What are the differences between Absolute URL and Relative URL?
Answer: Here are the differences between Absolute URLs and Relative URLs:

Absolute URLs are unique and self-contained, while Relative URLs are context-dependent and are typically used for internal links within the same website. This choice simplifies website management and improves flexibility.
In simple words: An Absolute URL is a full address that works from anywhere, like `http://www.example.com/page.html`. A Relative URL is a shorter address that only works from a specific place on a website, like `/images/pic.jpg`, assuming you are already on that website.

🎯 Exam Tip: The key distinction is that an absolute URL is complete and self-sufficient, whereas a relative URL needs a base URL to be resolved and is used for linking within the same site.

 

Question 5. Write a note on the domain name.
Answer: A domain name is a human-friendly name that identifies a website or resource on the internet, such as `google.com`. It is a sequence of labels that are separated by dots (.). For example, in `www.example.com`, `www`, `example`, and `com` are labels. Domain names are read from the lowest level (leaf node) to the highest level (root node). The root node is often represented as a NULL string, meaning the domain name always ends with a dot, even if it's not explicitly written. This hierarchical structure helps organize and manage the vast number of websites online.
In simple words: A domain name is a website's easy-to-remember name, like "google.com". It's made of parts called labels, separated by dots, and is read from right to left. The very end (the root) is like an invisible dot.

🎯 Exam Tip: Define a domain name as a sequence of dot-separated labels. Highlight that it's read from leaf to root (right to left) and the root is an implicit null string (represented by a trailing dot).

 

Question 6. Differentiate web address and URL
Answer: Here's how a Web Address and a URL differ:

Essentially, a Web Address is a more general, user-friendly term for the identifier of a website, often referring to the domain name. In contrast, a URL is a technical term for the complete string that specifies the location and access method for any resource on the internet. All web addresses are URLs, but not all URLs are necessarily considered "web addresses" in common usage (e.g., a URL for an FTP server might not be called a web address).
In simple words: A "Web Address" is usually the easy-to-remember name of a website, like "google.com". A "URL" is the full technical address that tells your computer exactly how to find any kind of content on the internet, whether it's a website, a picture, or a video.

🎯 Exam Tip: While often used interchangeably, clarify that "Web Address" is a common term for a website's domain, whereas a "URL" is the precise technical standard for locating any resource on the web.

Part IV

Explain In Detail

 

Question 1. Explain briefly the components of DNS.
Answer: The Domain Name System (DNS) has three important components that work together to manage and translate domain names into IP addresses. These components are:
1. Namespace
2. Name server
3. Zone

1. Name Space:
The domain names must be unique and appropriate, chosen from a namespace. The namespace can be arranged in two ways:
* **Flat name space:** This is where a name is directly assigned to an IP address. It is simple but cannot be used in large systems because it's hard to avoid similar names and manage them from one central place.
* **Hierarchical name space:** In this system, names are made up of several parts. The first part might show the type of organization (e.g., `.com`), the second part might be the organization's name (e.g., `google`), and the third part might be a department (e.g., `mail`). This design helps organize and manage many names in a decentralized way. The domain name space itself is the top-level element, called level 0, and it can have a maximum of 128 levels (0 to 127). The root element is often represented as a NULL string (empty string), and nodes below it have labels and domain names.

2. Name Servers:
Storing all domain name information in one place would be inefficient and unreliable for the entire world. Instead, this information is distributed among many computers called name servers. A name server is a key part of the DNS. It translates domain names into IP addresses and contains a database of domain names and their corresponding IP addresses. When you search for a website, your Local Name Server (provided by your Internet Service Provider) asks different name servers until one finds the correct IP address for that domain name and returns it to you. There are three types of Name Servers:
* **Root Name Server:** This is the top-level server for the entire DNS tree, managed by ICANN. There are 13 such servers.
* **Primary/Master Name Server:** This server holds the main, updatable records for a zone.
* **Secondary/Slave Name Server:** This server has a copy of the primary server's files, helping to reduce the workload on the master server by sharing queries.

3. Zone:
The entire namespace is divided into many different zones. A zone is a connected area that a server has access to. It is defined as a group of continuous domains and sub-domains. If a zone only has one domain, then the zone and the domain are the same. Each zone contains a database called a zone file. DNS servers use these zone files to respond to queries about hosts within their zone. There are two copies of zone files: a Master file and a Slave file, which helps ensure data redundancy and availability.
In simple words: DNS works with three main parts. First, the **Namespace** is how names are organized, either simply (flat) or in many layers (hierarchical). Second, **Name Servers** are computers that store website names and their number addresses. They help find the right addresses when you go online. There are different kinds of name servers, like root servers and master/slave servers. Third, a **Zone** is a section of the internet that a server manages, holding all the name details for that area.

🎯 Exam Tip: Explain each DNS component (Namespace, Name Servers, Zone) clearly. For Namespace, differentiate between flat and hierarchical. For Name Servers, mention their role in translation and briefly list the three types. For Zone, define it as an administrative area and its relation to domain files.

 

Question 1. Explain briefly the components of DNS.
Answer: The Domain Name System (DNS) has three key components that work together. These are the Namespace, Name Server, and Zone.
1. Name Space: Domain names need to be unique and well-chosen from a namespace. This namespace can be set up in two ways:

• Flat name space: Here, a name is directly linked to an IP address.
• Hierarchical name space: In this setup, names are made of several parts. The first part shows the type of organization, the second part shows the organization's name, and the third part shows the department.

The DNS was designed to use a hierarchical namespace to organize domain names efficiently.
2. Name Servers: A huge amount of information needs to be stored for domain names. It would be inefficient for a single system to store all this data and respond to requests from everywhere. If one system fails, all data would be lost. Name Servers are a main part of DNS, translating domain names into IP addresses. Each Name Server stores a DNS database with domain names and their IP addresses. Many servers are used globally to handle the large number of domain names and ensure reliability. When you search for a website, your Local Name Server (from your internet provider) asks different Name Servers until one finds the correct IP address. Finally, it sends that IP address back to your computer so you can access the domain. This distributed system helps manage the vast amount of internet data effectively.
3. Zone: The entire namespace is divided into different zones, which represent the area a server has access to. A zone is a group of connected domains and sub-domains. If a zone only has one domain, then the zone and the domain are considered the same. There are two types of zone files available: a Master file and a Slave file.
In simple words: DNS works like a phone book for the internet. It uses namespaces, name servers, and zones to turn easy-to-remember website names into computer-friendly IP addresses.

🎯 Exam Tip: Remember the three main components of DNS and explain how each contributes to the system's function, especially the translation of domain names to IP addresses.

 

Question 2. Classify and Explain the IP address.
Answer: An Internet Protocol (IP) address is a unique number that identifies a device on a network. It acts like a logical address in the network layer, similar to how a house number helps find a specific home in a street. It helps to find a particular computer or host system within the entire network. With more and more devices connecting to networks, there's a need for more addresses, which led to the development of IPv4 and IPv6.
IPv4 Address:

• An IPv4 address is a 32-bit unique address given to a computer system.
• However, two systems cannot have the exact same IP address.
• If a network has many connections, it needs a corresponding number of IP addresses.
• The address space is the total number of unique addresses that can be created by that protocol.
• This number is determined by how many bits the protocol uses.
• If a protocol uses 'n' bits, then \( 2^n \) addresses can be formed. So, for IPv4, \( 2^{32} \) addresses can be created.
• IPv4 addresses can be shown in two ways:
  • Binary notation: The address is shown as 32-bit binary values (e.g., 00111001 10001001 111000 00000111).
  • Dotted-decimal notation: The address is written in decimal format, with parts separated by dots (e.g., 128.143.137.144).

IPv6 Address:

• An IPv6 address is a 128-bit unique address given to a computer system.
• This allows for a much larger number of addresses, specifically \( 2^{128} \).
• In an IPv6 address, the 128 bits are split into eight blocks, each 16 bits long.
• Each block is then converted into a 4-digit hexadecimal number, and these blocks are separated by colon symbols (e.g., 2001:0000:3231:DFE1:0063:0000:0000:F EFB.a). IPv6 was developed to handle the massive increase in internet-connected devices.

In simple words: IP addresses are like unique ID numbers for devices on the internet. There are two main types: IPv4, which uses 32 bits and is written with dots, and IPv6, which uses 128 bits and is written with colons and hexadecimal numbers, allowing for many more addresses.

🎯 Exam Tip: When explaining IP addresses, clearly differentiate between IPv4 and IPv6 by mentioning their bit lengths and the notation used for each. Highlight why IPv6 was needed.

 

Question 3. Explain about the name server?
Answer: Name servers are essential components of the Domain Name System (DNS) that store and provide domain name information.

1. The amount of information needed for the Domain Namespace is very large. If a single system were to store it all, it would be inefficient and unable to handle requests from around the world. It would also be unreliable, as a failure would make the data inaccessible.
2. To solve this problem, the information is spread across many computers. This is done by dividing the entire domain name space into many domains and subdomains.
3. DNS also allows domains to be further divided, creating a hierarchical system of servers. This approach solves the problem of storing and managing vast amounts of data efficiently.
4. Name servers store the data and give it to clients when they ask for it. Name Servers are special programs that run on physical systems and keep all the zone data.
5. A Name Server is a key part of the Domain Name System (DNS) because it translates domain names into IP addresses.
6. Each name server has a DNS database containing domain names and their matching IP addresses.
7. Since there's a need to store many domain names for global use, many servers are used in a hierarchical structure.
8. Name servers perform the crucial task of finding domain names. When you search for a website, your Local Name Server (provided by your Internet Service Provider or ISP) asks different name servers until one finds the correct IP address. This IP address is then sent back to your computer for you to access that domain name.

Types of Name Servers:There are three types of Name Servers that manage the entire Domain Name System:
(i) Root Name Server – This is the top-level server that holds the entire DNS tree. It is managed by ICANN, and there are 13 such servers globally.
(ii) Primary/Master Name Server – This server contains the actual zone resource records. Domain name holders, like organizations, can update these records.
(iii) Secondary/Slave Name Server – This server keeps a copy of the primary server's files. It does not have the power to make updates but helps reduce the workload on the master server by handling some of the queries.
In simple words: Name servers are like special computers that store the internet's address book. They help turn website names into numerical IP addresses so your computer can find them. There are different types, like root servers and primary/secondary servers, all working together to keep the internet running smoothly.

🎯 Exam Tip: When describing name servers, explain their role in translating domain names to IP addresses and list the three types, briefly detailing the function of each (Root, Primary/Master, Secondary/Slave).

 

Question 4. What is domain name space? Explain.
Answer: The domain name space is a structured system designed to achieve a hierarchical namespace, which organizes domain names.

• This system represents names as a tree-like structure, with a root element at the very top. This tree can have a maximum of 128 levels, starting from level 0 (the root) up to level 127.
• The root element of the domain namespace is at the topmost level, known as level 0.
• The root element always stands for an empty string, or "NULL string."
• The level below the root element consists of nodes, which are children of the root. Each node in this tree has a label and a domain name.

Label:

• A label is a string that can have a maximum length of 63 characters.
• Each node at the same level must have different labels to ensure the uniqueness of each domain name.
• In simpler terms, labels are the actual names given to domains.
• A domain itself is a sub-tree within the domain name space tree structure. This domain can be further divided into smaller subdomains.

Domain name:

• A domain name is a sequence of labels. In a domain name, these labels are separated by a dot (.).
• Domain names are always read from the lower level (the leaf node) to the higher level (the root node).
• Since the root node represents a NULL string, all domain names technically end with a dot.

Basic rules of Domain names:

• A domain name can include alphabets from 'a' through 'z' and digits from '0' through '9'.
• Hyphens are allowed, but they cannot be the first character of a domain name.
• Spaces are not allowed within domain names.
• Special symbols such as !, $, &, and others are not permitted.
• The maximum length for an entire name can be 253 characters.
• Domain names are not case-sensitive, meaning they can be written using uppercase, lowercase, or a mix of both. For example, "example.com" is the same as "Example.com".

In simple words: The domain name space is like a big family tree for internet addresses. It's organized in levels, with a main root at the top. Each part of an address is a "label," and these labels follow certain rules, like using letters, numbers, and hyphens, but no spaces or special symbols.

🎯 Exam Tip: When explaining domain name space, describe its hierarchical structure, the role of labels, and the basic rules for creating valid domain names, including length and character restrictions.

 

Question 5. Explain how the DNS is working.
Answer: The Domain Name System (DNS) works by translating human-readable domain names into machine-readable IP addresses through a series of steps:

1. When a user types a URL (which includes a protocol, domain name, folder name, and file name) into a web browser, the system first checks its local DNS cache. This cache stores recently resolved IP addresses.
2. If the IP address for that domain name is found in the cache, the information is quickly retrieved from there. This makes browsing faster.
3. If the IP address is not in the cache, the system needs to perform a DNS query. It asks a resolver (usually provided by the Internet Service Provider or ISP) for the IP address.
4. Each resolver also has its own cache. If the information is found there, it is retrieved and sent back to the user's system.
5. If the resolver's cache doesn't have the IP address, the query is then sent to the next level of domain servers, specifically the Top-Level Domain (TLD) server. The TLD server looks at the request and points the query to the correct name servers that handle that specific domain. This process continues up the hierarchy until the IP address is found.
6. The query continues to be passed to higher-level domains until it is successfully resolved. Finally, the mapping (the IP address) and the record are sent back to the resolver, which checks if the returned value is a valid record or an error.
7. After confirmation, the resolver sends the record (IP address) back to the user's computer browser, which then uses it to display the website.

In simple words: When you type a website address, DNS quickly finds the correct numerical address (IP address) for that website, first checking local memories and then asking a series of servers until it gets the answer, allowing your browser to open the page.

🎯 Exam Tip: Detail the step-by-step process of a DNS query, starting from the user's browser, through local caches, resolvers, and TLD servers, until the IP address is returned.

 

12th Computer Applications Guide DNS (Domain Name System) Additional Important Questions and Answers

Part A

Choose The Correct Answers:

 

Question 1. Expand DNS?
(a) Direct Name Server
(b) Domain Name System
(c) Domain Name Security
(d) Direct Name Service
Answer: (b) Domain Name System
In simple words: DNS is a computer system that translates website names into numbers so computers can understand them.

🎯 Exam Tip: Remember common acronyms and their full forms, especially in computer science, as they are frequently tested.

 

Question 2. For the communication to takes place, the information should pass through ....... layers
(a) six
(b) two
(c) end to end
(d) Seven
Answer: (d) Seven
In simple words: For computers to talk to each other, information often travels through seven different steps or layers, like different stages in a journey.

🎯 Exam Tip: Relate this question to the OSI model, which defines seven layers for network communication. Understanding the model helps recall this fact.

 

Question 3. While typing a web address, DNS translates it into a machine-friendly IP address.
(a) True
(b) False
Answer: (a) True
In simple words: Yes, when you type a website name, DNS changes it into a numerical IP address that computers use to find the website.

🎯 Exam Tip: Understand the primary function of DNS as a translator between human-readable domain names and numerical IP addresses.

 

Question 4. DNS provides the domain name to IP address mapping through ......
(a) IP address
(b) Name Servers
(c) domain
(d) URL
Answer: (b) Name Servers
In simple words: Name servers are special computers that act like a directory, matching website names to their unique numerical addresses.

🎯 Exam Tip: Focus on the specific role of name servers in the DNS hierarchy as the primary entities responsible for domain-to-IP mapping.

 

Question 5. Paul V. Mockapetris together with ............. invented the Internet Domain Name System (DNS).
(a) Jon Postel
(b) Dennis Ritchie
(c) James Gostling
(d) Carrelli
Answer: (a) Jon Postel
In simple words: Paul V. Mockapetris and Jon Postel were key people who created the system that helps us use easy-to-remember names for websites instead of long numbers.

🎯 Exam Tip: Knowing key figures and their contributions in computing history can be useful for general knowledge questions.

 

Question 6. IP stands for ............
(a) Input process
(b) Input
(c) Internet Protocol
(d) Internet Power
Answer: (c) Internet Protocol
In simple words: IP means Internet Protocol, which is a set of rules for how data moves across the internet.

🎯 Exam Tip: Just like DNS, IP is a fundamental acronym in networking; ensure you know its full form and basic meaning.

 

Question 7. ........... is available below the root domain.
(a) IANA
(b) IPv4
(c) IPv6
(d) TLD
Answer: (d) TLD
In simple words: Top-Level Domains (like .com, .org) are the next level down from the main, unseen root of the internet's naming system.

🎯 Exam Tip: Visualize the DNS hierarchy: the root is at the top, followed by Top-Level Domains (TLDs), then second-level domains, and so on.

 

Question 8. How many IP addressing methods are there?
(a) 1
(b) 2
(c) 3
(d) 4
Answer: (b) 2
In simple words: There are two main types of IP addresses used today: IPv4 and IPv6.

🎯 Exam Tip: The two main IP addressing methods are IPv4 and IPv6; remember their existence as the foundational ways to identify devices on a network.

 

Question 9. Which of the following is a program running on a dedicated machine which handles the queries of www end-user?
(a) Webserver
(b) Web Host
(c) DNS
(d) HTML
Answer: (a) Webserver
In simple words: A web server is a computer program that manages and responds to requests from users looking for web pages.

🎯 Exam Tip: Understand that a web server's core function is to "serve" web content to users upon request, acting as the intermediary between the user's browser and the website files.

 

Question 10. If the protocol uses 'n' bits then the address space of that protocol would be
(a) n
(b) \( n^2 \)
(c) 2n
(d) \( 2^n \)
Answer: (d) \( 2^n \)
In simple words: If you have 'n' bits (like on-off switches), you can make \( 2^n \) different combinations or addresses.

🎯 Exam Tip: This is a basic principle in computer science: the number of possible unique values for 'n' bits is always \( 2^n \).

Fill in The Blanks.

 

Question 1. ............. is a logical address used to uniquely identify a computer over the Network.
Answer: IP address
In simple words: An IP address is like a unique number plate for a computer on the internet.

🎯 Exam Tip: Distinguish between physical (MAC) and logical (IP) addresses, understanding IP's role in network identification.

 

Question 2. IPv4 address is a ............ unique address given to a computer or a device.
Answer: 32-bit
In simple words: IPv4 uses 32 bits to create a unique address for each device.

🎯 Exam Tip: Always remember the bit length for IPv4 (32-bit) and IPv6 (128-bit) as this is a common point of confusion.

 

Question 3. IPv6 address is a ............ unique address given to a computer or a device.
Answer: 128 bit
In simple words: IPv6 uses 128 bits to give a unique address, which allows for many more addresses than IPv4.

🎯 Exam Tip: Knowing the bit length helps understand the vastly larger address space of IPv6 compared to IPv4.

 

Question 4. ............ follows Hexadecimal number notation.
Answer: IPv6
In simple words: IPv6 addresses are written using a mix of numbers and letters, called hexadecimal notation.

🎯 Exam Tip: Remember that hexadecimal notation with colons is characteristic of IPv6 addresses, unlike the dotted-decimal of IPv4.

 

Question 5. ............ is the address of a document on the Internet.
Answer: URL (Uniform Resource Locator)
In simple words: A URL is the full web address that points to a specific page or file on the internet.

🎯 Exam Tip: Recognize URL as the standard way to specify the location of resources on the World Wide Web.

 

Question 6. ............ contains only folder name and the file name or just the file name.
Answer: Relative URL
In simple words: A relative URL is a short web address that only tells you the file or folder name, assuming you are already in the right place on a website.

🎯 Exam Tip: Differentiate between absolute URLs (full path) and relative URLs (partial path based on current location).

 

Question 7. ............ is a tree-like structure with a root element on the top.
Answer: Domain namespace
In simple words: The domain namespace is like a family tree that organizes all the website names, starting from a single main point at the top.

🎯 Exam Tip: Understand that the hierarchical nature of the domain namespace is fundamental to how DNS organizes information.

 

Question 8. The domain name is always read from the .............
Answer: leaf node to root node
In simple words: When reading a domain name, you start from the most specific part (like 'com' in example.com) and move towards the general root.

🎯 Exam Tip: Remember the "right-to-left" reading of domain names in terms of hierarchy (e.g., .com is a TLD, then example, then www).

 

Question 9. In the domain name space (DNS) tree structure ............... is a substructure tree.
Answer: domain
In simple words: In the DNS system, a 'domain' is a smaller tree-like part within the larger tree structure.

🎯 Exam Tip: A domain is a logical grouping of computers or resources within the broader DNS hierarchy.

 

Question 10. ............ are programs that run on a physical system and store all the zone data.
Answer: Name Servers
In simple words: Name servers are special programs that store all the information about a "zone" or part of the internet's address book.

🎯 Exam Tip: Name servers are the hardware/software entities that host and manage the actual DNS zone files.

 

Question 11. ............ provides to clients when queried by them.
Answer: Name Servers
In simple words: Name servers give clients the information they ask for when trying to find a website.

🎯 Exam Tip: Reiterate the function of name servers in responding to client queries for domain resolution.

 

Question 12. ............ non-profit organization which regulates the Internet.
Answer: ICANN
In simple words: ICANN is an important organization that helps manage and organize how the internet works, especially with domain names.

🎯 Exam Tip: ICANN (Internet Corporation for Assigned Names and Numbers) is crucial for global internet governance, particularly for domain name allocation.

 

Question 13. ............ is an affiliated authority of ICANN.
Answer: IANA (Internet Assigned Numbers Authority)
In simple words: IANA is a group that works under ICANN and helps manage important internet numbers and names.

🎯 Exam Tip: IANA is responsible for the global coordination of IP addressing, ASN allocation, and root zone management under ICANN's oversight.

 

Question 14. ............ is a group of contiguous domains and subdomains in the Domain Name Space.
Answer: Zone
In simple words: A 'zone' in the DNS system is a related group of domains and subdomains that are managed together.

🎯 Exam Tip: Understand that a zone represents an administrative boundary within the DNS hierarchy, containing authoritative information for a part of the domain name space.

Assertion And Reason

 

Question. Assertion (A): Domain Name System (DNS) maintains all the directory of domain names and helps us to access the websites using the domain names. Reason(R): t translates the domain name into an IP address.
Answer: (a) Both (A) and (R) are correct and (R) is the correct explanation of (A)
In simple words: Both statements are true: DNS keeps a list of all domain names to help us find websites, and it does this by changing domain names into IP addresses. The second statement explains the first.

🎯 Exam Tip: In Assertion-Reason questions, first check if both statements are individually true. If so, then determine if the Reason directly explains the Assertion.

 

Question 2. Assertion (A): IPv4 address is a 64-bit unique address. Reason(R): There are two ways to represent the IP address: Binary notation, Dotted-decimal notation.
Answer: (d) (A) is false and (R) is true
In simple words: The first statement is false because IPv4 uses 32 bits, not 64. The second statement is true because IP addresses can be shown in binary or dotted-decimal forms.

🎯 Exam Tip: Clearly remember the bit length of IPv4 (32-bit) to avoid common mistakes. The methods of representation (binary, dotted-decimal) are distinct facts.

 

Question 3. Assertion (A): Label is a string Reason(R): Label can have a maximum of 63 characters
Answer: (a) Both (A) and (R) are correct and (R) is the correct explanation of (A)
In simple words: Both statements are correct: a label is indeed a string of characters, and it can be up to 63 characters long. The second statement gives a detail about the first.

🎯 Exam Tip: Understand the definition and constraints of a "label" within the DNS hierarchy, as it's a fundamental building block of domain names.

 

Question 4. Assertion (A): Domain namespace is a tree-like structure with a root element on the top. Reason(R): it can have a maximum of 127 levels starting from the root element
Answer: (c) (A) is true and (R) is false
In simple words: The first statement is true because the domain namespace is organized like a tree with a root at the top. The second statement is false because it can have up to 128 levels (level 0 to level 127), not just 127 levels counting from the root.

🎯 Exam Tip: Be precise with numerical facts. The total number of levels in the DNS tree is 128 (level 0 through level 127), not 127 levels in total.

 

Question 5. Assertion (A): The Resolver is a service of ICANN Reason(R): Resolver, a client/server application, initiates the process of resolving the domain names.
Answer: (d) (A) is false and (R) is true
In simple words: The first statement is false because a resolver is not a service of ICANN, but a program that starts the process of finding domain names. The second statement is true because a resolver does start the process of translating domain names into IP addresses.

🎯 Exam Tip: Clarify the role of a resolver (software to query DNS) versus ICANN (governing body). They have distinct functions.

 

Question 6. Assertion (A): URL Stands for Uniform Resource Locator Reason(R): URL- the address of a specific web page or file on the Internet.
Answer: (a) Both (A) and (R) are correct and (R) is the correct explanation of (A)
In simple words: Both statements are true: URL stands for Uniform Resource Locator, and it is indeed the address for a specific web page or file online. The second statement explains what a Uniform Resource Locator actually is.

🎯 Exam Tip: Understand that the full form of URL (Uniform Resource Locator) describes its function as an address for web resources.

Find The Odd One On The Following

 

Question 1.
(a) File Name
(b) Protocol
(c) HTML
(d) Host Name
Answer: (c) HTML
In simple words: File Name, Protocol, and Host Name are all components of a web address or network communication. HTML is a markup language used to create web pages, making it the odd one out.

🎯 Exam Tip: When finding the odd one out, think about the category each item belongs to. Here, three are parts of addressing/communication, and one is a content language.

 

Question 2.
(a) Label
(b) Namespace
(c) Name server
(d) Zone
Answer: (a) Label
In simple words: Namespace, Name server, and Zone are big parts of how domain names work. A Label is just a smaller piece of a domain name, not a major system component like the others.

🎯 Exam Tip: Understand the hierarchy in DNS. Namespace, Name Server, and Zone are the main architectural elements, while a Label is a granular detail within the naming structure.

 

Question 4.
(a) Tree Like Structure
(b) 128 Levels
(c) NULL string
(d) Flat Namespace
Answer: (d) Flat Namespace
In simple words: Tree-like structure, 128 levels, and NULL string are all ideas connected to how a hierarchical domain name system is built. A 'Flat Namespace' is a different, simpler way of naming things that does not have these features, so it is the odd one.

🎯 Exam Tip: Distinguish between flat and hierarchical naming systems. Flat namespaces are simpler but have scalability issues, while hierarchical systems are complex but more efficient for large networks.

 

Question 5.
(a) .com
(b) -ta
(c) .gov
(d) .nic
Answer: (b) -ta
In simple words: .com, .gov, and .nic are all types of top-level domain names you see on the internet. '-ta' is not a recognized domain name format, making it the one that doesn't fit.

🎯 Exam Tip: Familiarize yourself with common Top-Level Domains (TLDs) like .com, .org, .net, and country-code TLDs, as well as rules for valid domain name characters.

 

Question 6.
(a) com
(b) net
(c) bd
(d) info
Answer: (c) bd
In simple words: 'com', 'net', and 'info' are all generic Top-Level Domains (gTLDs). 'bd' is a country code Top-Level Domain (ccTLD) for Bangladesh, so it is different from the others.

🎯 Exam Tip: Understand the difference between generic TLDs (like .com, .org) and country-code TLDs (like .in, .uk, .bd). This distinction is important in domain naming.

 

Question 7.
(a) India
(b) Malaysia
(c) Singapore
(d) Srilanka
Answer: (b) Malaysia
In simple words: India, Singapore, and Srilanka are names of countries. If this question refers to a specific list of domains related to Tamil language (as seen in a previous question), then Malaysia might be the odd one out from that particular context.

🎯 Exam Tip: For odd one out questions, look for shared characteristics among the options and identify the one that doesn't fit the pattern based on the topic. In domain names, classification can be by type (gTLD, ccTLD) or specific lists.

 

Question 8.
(a) Name server
(b) DNS Database
(c) IP Address
(d) HTTP
Answer: (d) HTTP
In simple words: Name server, DNS Database, and IP Address are all direct parts of how the Domain Name System (DNS) works to find website locations. HTTP is a protocol used for transferring web pages, not a component within the DNS structure itself, so it's the different one.

🎯 Exam Tip: Differentiate between protocols (like HTTP for web communication) and infrastructure components (like Name Servers, DNS Databases, and IP Addresses for name resolution).

 

Question 9.
(a) Primary Name Server
(b) Secondary Name Server
(c) Node Name Server
(d) Root Name Server
Answer: (c) Node Name Server
In simple words: Primary, Secondary, and Root Name Servers are actual types of name servers used in the DNS. 'Node Name Server' is not a standard type of name server in the DNS system, making it the odd one.

🎯 Exam Tip: Know the specific classifications of DNS name servers (Root, Top-Level, Authoritative, Primary, Secondary) to correctly identify non-standard terms.

 

Question 10.
(a) Host
(b) Webserver
(c) DNS server
(d) Namespace
Answer: (d) Namespace
In simple words: A Host, Webserver, and DNS server are all actual computers or systems that perform specific roles in a network. A Namespace is a way of organizing names, not a physical server itself, so it's the odd one out.

🎯 Exam Tip: Understand that a 'namespace' is a logical concept for organizing names, distinct from physical or virtual servers that handle requests within that space.

 

Question 11.
(a) Name server
(b) Resolver
(c) ICANN
(d) Zone
Answer: (c) ICANN
In simple words: Name server, Resolver, and Zone are all active components or parts of the Domain Name System that make it work. ICANN is an organization that manages and coordinates these systems, but it's not a part of the system's day-to-day operation like the others.

🎯 Exam Tip: Differentiate between operational components of DNS (servers, resolvers, zones) and the governing bodies or organizations (like ICANN) that oversee them.

 

Question 12.
(a) 32 bit
(b) Binary Notation
(c) Hexadecimal
(d) Dotted decimal
Answer: (c) Hexadecimal
In simple words: 32 bit, Binary Notation, and Dotted decimal are all ways or features used to describe IPv4 addresses. Hexadecimal notation is used for IPv6 addresses, not IPv4, making it the different one.

🎯 Exam Tip: Remember that IPv4 uses 32-bit addresses, commonly represented in dotted-decimal or binary. IPv6 uses 128-bit addresses, commonly represented in hexadecimal.

 

Question 13.
(a) WHOIS
(b) ICANN
(c) IAN
(d) FORTRAN
Answer: (d) FORTRAN
In simple words: WHOIS, ICANN, and IANA are all related to domain name registration and internet governance. FORTRAN is an old programming language, which has nothing to do with domain names or internet management, so it's clearly the odd one.

🎯 Exam Tip: Knowing common acronyms related to internet infrastructure (like ICANN, IANA, WHOIS) helps in identifying unrelated terms like programming languages.

 

Question 14.
(a) 128bit
(b) 16block
(c) Hexadecimal
(d) Binary notation
Answer: (d) Binary notation
In simple words: 128-bit, 16-block, and Hexadecimal are all features or ways of describing IPv6 addresses. Binary notation, while used for some IP addressing, is not the primary way IPv6 is typically discussed or structured in terms of blocks and hexadecimal representation, making it somewhat of an outlier in this context.

🎯 Exam Tip: Focus on the specific characteristics of IPv6: 128-bit length, division into 16-bit blocks, and common representation using hexadecimal numbers.

 

Question 15.
(a) in
(b) cn
(c) gov
(d) pk
Answer: (c) gov
In simple words: 'in', 'cn', and 'pk' are all country code Top-Level Domains (ccTLDs) for India, China, and Pakistan, respectively. '.gov' is a generic Top-Level Domain (gTLD) used by government entities, not tied to a specific country's code, so it is the odd one.

🎯 Exam Tip: Remember that ccTLDs are two-letter country codes, while gTLDs are broader categories. This distinction helps in identifying the outlier.

Very Short Answers

 

Question 1. What is a domain?
Answer: A domain is like a single spot or point within the Domain Namespace, which is a big organized tree of names. It represents a specific part of the internet's naming structure.
In simple words: A domain is one unique name in the internet's naming system.

🎯 Exam Tip: Define a domain as a logical subdivision within the DNS hierarchy. Mentioning "single node" or "subtree" can secure full marks.

 

Question 2. What is Zone?
Answer: A zone is a section of the Domain Namespace. It's usually stored in a special file and represents a part of the domain name space that a specific server has authority over.
In simple words: A zone is a specific part of the internet's naming system that a server manages.

🎯 Exam Tip: Emphasize that a zone is a *subset* of the domain namespace and is typically managed by a specific name server through a zone file.

 

Question 3. What is Domain Name Space?
Answer: The Domain Name Space is the entire collection of all domain names, subdomains, and zones, organized in a tree-like structure. It is the complete naming system of the internet.
In simple words: Domain Name Space is the whole collection of all names used on the internet, like a big address book.

🎯 Exam Tip: Highlight that the domain name space is the *entire* hierarchical structure, encompassing all domains, subdomains, and zones.

 

Question 4. What is a Name Server?
Answer: A Name Server is a computer program that holds the database of domain names and their matching IP addresses. It helps translate human-readable domain names into machine-readable IP addresses.
In simple words: A Name Server is a special computer that stores website names and their number addresses.

🎯 Exam Tip: Focus on the primary function: a name server stores DNS records and translates domain names to IP addresses.

 

Question 5. What does the zone contain?
Answer: A zone can contain one or more subdomains. It basically includes all the domain name information for a specific part of the DNS hierarchy.
In simple words: A zone holds details for a domain and any smaller domains within it.

🎯 Exam Tip: Remember that a zone acts as an administrative boundary for managing a part of the DNS namespace, potentially including multiple subdomains.

 

Question 6. What does the server contain?
Answer: A server, in the context of DNS, can contain one or more zone files. These zone files hold all the records for the domains and subdomains that the server is responsible for.
In simple words: A DNS server stores special files called zone files, which have all the internet names it manages.

🎯 Exam Tip: Connect the server to its role in hosting zone files, which are the actual databases of domain information.

Domain Name Meaning

Part B

Short Answers

 

Question 1. Name the four parts of the URL?
Answer: A URL (Uniform Resource Locator) is made up of four main parts: the protocol, the hostname, the folder name, and the file name. Each of these parts works together to point to a specific resource on the internet. Depending on the application, additional information can be added, but these four are the common and fundamental components.
In simple words: A URL has four main sections: the rule for talking (protocol), the website's name (hostname), where files are kept (folder name), and the file's exact name.

🎯 Exam Tip: List the four components of a URL clearly: protocol, hostname, folder name, and file name. Providing a simple example can help illustrate each part.

 

Question 2. List the three components of DNS?
Answer: The three main components of the Domain Name System (DNS) are Namespace, Name Server, and Zone. These elements work together to create an organized and efficient system for translating domain names into IP addresses.
In simple words: The three parts of DNS are the overall naming system (Namespace), the computers that store names (Name Server), and the parts of the system a server manages (Zone).

🎯 Exam Tip: Memorize these three core components as they represent the fundamental architecture of the Domain Name System.

 

Question 3. What is a Label?
Answer: A label is a piece of text within a domain name that can be up to 63 characters long. Each level in a domain name's tree structure has its own label, and these labels must be different from each other at the same level to make sure each domain name is unique. Labels are essentially the individual names given to domains.
In simple words: A label is a small text part of a domain name, up to 63 characters long. Each label helps make sure the domain name is unique.

🎯 Exam Tip: Define a label by its maximum length (63 characters) and its role in ensuring uniqueness within a domain name. This is a crucial building block of DNS.

 

Question 4. Name the three domain names used in Tamil language?
Answer: The three domain names mentioned in Tamil language contexts often refer to countries or regions where Tamil is spoken or has cultural significance. These include India, Singapore, and Srilanka. These names are usually associated with country-code top-level domains like '.in', '.sg', and '.lk'.
In simple words: Three countries mentioned in Tamil language contexts for domain names are India, Singapore, and Srilanka.

🎯 Exam Tip: This question might test cultural or geographical context alongside technical knowledge. Always connect country names to their respective country code top-level domains (ccTLDs).

 

Question 5. What is the Inverse domain?
Answer: An inverse domain performs the opposite function of a regular DNS query. Instead of translating a domain name into an IP address, it takes an IP address and converts it back into a domain name. This is often used for security checks and logging.
In simple words: An inverse domain finds the website name when you only have its number address (IP address).

🎯 Exam Tip: Clearly state that inverse DNS mapping translates IP addresses to domain names, which is the reverse of a standard DNS query. This is also known as a reverse DNS lookup.

 

Question 6. What is Zone File?
Answer: A zone file is a special text file that contains a database of all the domain name records for a specific zone. Every zone that a name server manages has its own zone file, which stores information like IP addresses, mail server details, and more.
In simple words: A zone file is a database file that holds all the important information for a specific part of the internet's naming system.

🎯 Exam Tip: Define a zone file as the authoritative text database containing all DNS records for a particular zone, managed by a name server.

 

Question 7. What are the two copies of the zone file?
Answer: There are two main copies or types of zone files that are kept for a domain: the Masterfile and the Slave file. The Masterfile is the original, editable version, while the Slave file is a read-only copy that helps distribute the load and provides redundancy.
In simple words: The two copies of a zone file are called the Masterfile (the main one) and the Slave file (a backup copy).

🎯 Exam Tip: Identify Masterfile and Slave file as the two types, emphasizing their roles in primary/secondary server configurations for redundancy and load balancing.

 

Question 7. Write the demerits of the Flat namespace?
Answer: The major disadvantage of flat namespaces is that they are not suitable for large systems. This is because all names in a flat namespace must be unique across the entire system. Centralized control is required to prevent duplicate names and maintain order. This becomes very difficult and inefficient to manage as the system grows, leading to ambiguity and redundancy issues.
In simple words: Flat namespaces are not good for big systems because all names must be unique and one central group has to control everything, which is hard to do.

🎯 Exam Tip: Highlight the key drawbacks of flat namespaces: lack of scalability for large systems, the need for centralized control to avoid ambiguity, and potential for redundancy.

Part C

Explain In Brief Answer

 

Question 1. What are the fundamentals of URL?
Answer: A URL, which stands for Uniform Resource Locator, is a complete web address used to find a specific resource on the internet. It is made up of four fundamental parts:
• Protocol: This specifies how the resource should be accessed (e.g., http, https, ftp). It acts like a rulebook for communication.
• Domain name/Hostname: This is the unique name of the server where the resource is located (e.g., www.example.com). It's the human-readable address.
• Folders: This shows the directory path on the server where the resource is stored. It's like navigating through folders on a computer.
• Filename with extension: This is the exact name of the resource, including its file type (e.g., index.html, image.jpg, style.css). These parts work together to give a precise location for any file or page on the web, making it easy for browsers to find them.
In simple words: A URL is a web address with four main parts: the method (protocol), the website name (hostname), the folders where the file is, and the file's exact name. Together, they point to anything on the internet.

🎯 Exam Tip: Clearly define a URL and list its four core components, explaining the purpose of each. Using an example like "http://www.example.com/folder/file.html" can help illustrate each part.

 

Question 2. What is meant by Label?
Answer: A label is a piece of a domain name string that can have a maximum length of 63 characters. In the hierarchical structure of a domain name, each node at a particular level has a unique label. This uniqueness ensures that every domain name has its own individual identifier. Simply put, labels are the specific names given to different parts of domains within the DNS tree structure.
In simple words: A label is a small part of a domain name, up to 63 characters long. Each label helps make sure the domain name is unique.

🎯 Exam Tip: When explaining labels, highlight their maximum length and their role in creating unique identifiers within the DNS hierarchy, forming the segments between dots in a domain name.

 

Question 3. Write a note on Country top-level domain names.
Answer: Country Top-Level Domain (ccTLD) names are special domain extensions that use two-character country abbreviations, following international standards. These domains are assigned to specific countries or sovereign states. For example, '.in' is for India, '.us' for the United States, '.uk' for the United Kingdom, and '.jp' for Japan. These ccTLDs help organize the internet geographically and allow websites to be associated with a particular country. They are an important part of how internet addresses are structured globally.
In simple words: Country top-level domains use two letters, like '.in' for India, to show which country a website belongs to. They help sort websites by location.

🎯 Exam Tip: Define ccTLDs as two-character country abbreviations. Provide a few examples to illustrate the concept and mention their role in geographical organization.

 

Question 4. Explain the types of Name servers?
Answer: There are three main types of Name Servers that manage the entire Domain Name System (DNS) tree structure:
• Root Name Server: These are the top-level servers in the DNS hierarchy. They contain the entire DNS tree information and are maintained by ICANN. There are 13 logical root servers globally, which are crucial for the internet's operation.
• Primary/Master Name Server: This server holds the original, editable copies of the zone resource records for a specific domain. Any updates or changes to the domain's information are first made on this server.
• Secondary/Slave Name Server: This server keeps an exact copy of the zone files from a primary server. It does not have the authority to make changes directly but helps reduce the workload of the master server by answering queries. It also provides redundancy, ensuring that domain information is available even if the primary server goes offline.
In simple words: There are three main kinds of Name Servers: Root servers (top-level, managed by ICANN), Primary servers (hold original domain info), and Secondary servers (hold copies for backup and sharing work).

🎯 Exam Tip: List and briefly describe each of the three types of name servers (Root, Primary/Master, Secondary/Slave), highlighting their roles in the DNS hierarchy and data management.

Part IV

Explain In Detail

 

Question 1. Explain the Basic rules of Domain names?
Answer: Domain names must follow a specific set of rules to be valid and functional on the internet:
1. A domain name can include letters from 'a' through 'z', numbers from '0' through '9', and hyphens (-).
2. Hyphens are allowed within a domain name, but they cannot be used as the very first or last character of a domain name.
3. Spaces are strictly not allowed anywhere in a domain name.
4. Special symbols like '!', '$', '&', and '_' are not permitted.
5. The maximum length for a single label (the part between dots) within a domain name is 63 characters.
6. The entire name may be at most 253 characters long.
7. Domain names are generally not case-sensitive, meaning 'example.com' is treated the same as 'EXAMPLE.COM'. However, it's best practice to use lowercase. These rules help ensure that domain names are consistent and can be easily processed by DNS systems worldwide.
In simple words: Domain names can only have letters, numbers, and hyphens (not at the start or end). No spaces or special symbols are allowed. Each part between dots can be up to 63 characters, and the whole name can be up to 253 characters. Names are not case-sensitive.

🎯 Exam Tip: List the key rules for domain names: allowable characters, restrictions on hyphens, prohibition of spaces and special symbols, and the maximum length for labels and the full domain name. Mentioning case-insensitivity is also important.

 

Question 2. Write a note on the Hierarchical namespace?
Answer: A hierarchical namespace is a system where names are organized in a tree-like structure, similar to how folders are arranged on a computer. This structure helps manage a very large number of names efficiently and avoids problems that come with a simple "flat" list of names. In this system:
• To avoid the major disadvantage of the Flat namespace, the hierarchical namespace is used in large systems.
• The name is made up of several parts, where each part describes a different level of organization. For example, a name might show the type of organization (like '.com'), then the organization's name (like 'example'), and then a specific department or service (like 'www').
• This design allows the management of the namespace to be spread out, or decentralized. Instead of one central place controlling everything, different parts of the tree can be managed by different authorities. This makes the system more robust and easier to scale.
• The Domain Name System (DNS) itself was designed using a hierarchical namespace. It starts with a root element at the very top, and then branches out into many levels. This tree can have up to 128 levels, from level 0 (the root) to level 127, allowing for a vast number of unique names.
In simple words: A hierarchical namespace organizes names like a tree, with big categories at the top and smaller ones below. This helps manage many names easily and allows different parts to be controlled by different people. The internet's naming system (DNS) uses this method.

🎯 Exam Tip: Explain that a hierarchical namespace organizes names in a tree structure to manage large numbers of unique identifiers. Emphasize its benefits like decentralization, scalability, and how DNS implements it with a root and multiple levels.