Network

Question 1

What is the difference between HTTP and HTTPS?

Answer 1

HTTP (Hypertext Transfer Protocol) is used for transmitting data over the web. HTTPS adds encryption using SSL/TLS, ensuring data is secure in transit.

Question 2

What is DNS, and how does it work?

Answer 2

DNS (Domain Name System) translates human-readable domain names (e.g., google.com) into IP addresses. It works through a hierarchy of servers:

• Recursive Resolver queries.
• Root Server directs to a TLD server.
• TLD Server directs to an authoritative server.
• Authoritative Server provides the IP address.

Question 3

What is an IP address, and what are the differences between IPv4 and IPv6?

Answer 3

An IP address is a unique identifier for devices on a network:
- IPv4: 32-bit addresses (e.g., 192.168.0.1).
- IPv6: 128-bit addresses (e.g., 2001:0db8:85a3:0000:0000:8a2e:0370:7334) to accommodate more devices.

Question 4

What is the TCP/IP model?

Answer 4

TCP/IP is a suite of protocols for communication over the internet. Key layers:
- Application Layer (e.g., HTTP, FTP).
- Transport Layer (e.g., TCP, UDP).
- Internet Layer (e.g., IP, routing).
- Network Access Layer (e.g., Ethernet).

Question 5

What is the difference between TCP and UDP?

Answer 5

• TCP: Connection-oriented, ensures reliable delivery, used for data like webpages and emails.
• UDP: Connectionless, faster but less reliable, used for streaming or gaming.

Question 6

What are ports in networking, and why are they important?

Answer 6

Ports are endpoints in networking used to identify specific processes or services. For example:

• Port 80: HTTP.
• Port 443: HTTPS.

Question 7

What is DNS caching, and how does it improve performance?

Answer 7

DNS caching stores resolved IP addresses locally (e.g., in your browser or OS) to avoid repeated queries, reducing latency and speeding up browsing.

Question 8

What are common HTTP methods, and how are they used?

Answer 8

GET: Retrieve data.
POST: Send data to create resources.
PUT: Update/replace resources.
DELETE: Remove resources.
PATCH: Partially update resources.

Question 9

What are HTTP status codes, and give examples of common ones.

Answer 9

HTTP status codes indicate the result of an HTTP request:

• 200: OK.
• 401: UnAuthorised.
• 404: Not Found.
• 500: Internal Server Error.

Question 10

What is Cross-Origin Resource Sharing (CORS)?

Answer 10

CORS is a security policy that controls how resources on a server can be accessed by clients from other origins. It’s implemented using HTTP headers like Access-Control-Allow-Origin.

Question 11

What are WebSockets, and how do they differ from HTTP?

Answer 11

WebSockets provide a persistent, full-duplex communication channel between the client and server, unlike HTTP, which is stateless and request-response-based.

Question 12

What is latency in networking?

Answer 12

Latency is the time it takes for a data packet to travel from the source to the destination.

Question 13

What is a Content Delivery Network (CDN)?

Answer 13

A CDN is a distributed network of servers that cache and deliver content (e.g., images, videos) from the nearest location to the user, reducing latency and improving load times.

Question 14

What is load balancing, and why is it important?

Answer 14

Load balancing distributes incoming traffic across multiple servers to ensure reliability, prevent overload, and improve performance.

Question 15

What are the layers of the OSI model?

Answer 15

The OSI model has seven layers:
- Physical.
- Data Link.
- Network.
- Transport.
- Session.
- Presentation.
- Application.

Question 16

What is TLS/SSL, and why is it used?

Answer 16

TLS (Transport Layer Security) and SSL (Secure Sockets Layer) encrypt data in transit, ensuring secure communication over the internet. HTTPS relies on TLS/SSL.

Question 17

What is a proxy server, and how does it work?

Answer 17

A proxy server acts as an intermediary between a client and the internet, providing anonymity, caching, and security features.

Question 18

What is NAT, and why is it used?

Answer 18

NAT (Network Address Translation) translates private IP addresses within a local network to a single public IP address, allowing multiple devices to share one internet connection.

Question 19

What is packet switching?

Answer 19

Packet switching is a method of transmitting data by dividing it into packets, which are routed independently and reassembled at the destination.

Question 20

What are ping and traceroute commands used for?

Answer 20

• Ping: Tests connectivity between two devices by sending ICMP echo requests.
• Traceroute: Tracks the route data packets take to reach a destination, showing each hop along the way.