Interview questions -2

Networking (25 Questions)

1. Difference between a hub, switch, and router: → Hub broadcasts data to all ports; switch forwards data to specific MAC addresses; router connects different networks.

2. Explain the OSI model and its layers: → Seven layers — Physical, Data Link, Network, Transport, Session, Presentation, Application.

3. Difference between TCP and UDP: → TCP is connection‑oriented and reliable; UDP is connectionless and faster.

4. Define IP address classes: → Class A (1–126), B (128–191), C (192–223), D (224–239 multicast), E (240–255 experimental).

5. What is subnetting and why is it used? → Divides networks into smaller subnets for efficient IP management and security.

6. Explain DHCP and its purpose: → Automatically assigns IP addresses to devices on a network.

7. What is DNS and how does it work? → Translates domain names into IP addresses using hierarchical name servers.

8. Difference between public and private IP addresses: → Public IPs are globally routable; private IPs are used within local networks.

9. What is NAT and why is it important? → Network Address Translation converts private IPs to public IPs for internet access.

10. Explain VLANs and their benefits: → Virtual LANs logically segment networks for better security and management.

11. Difference between static and dynamic routing: → Static routes are manually configured; dynamic routes use protocols like OSPF or RIP.

12. What is a default gateway? → The router interface that connects a local network to external networks.

13. Explain ARP and its role: → Address Resolution Protocol maps IP addresses to MAC addresses.

14. Difference between IPv4 and IPv6: → IPv4 uses 32‑bit addresses; IPv6 uses 128‑bit addresses with larger space and security.

15. Bandwidth vs. latency: → Bandwidth is data capacity; latency is delay in transmission.

16. Concept of packet switching: → Data is broken into packets and sent independently across the network.

17. What is a firewall? → A security device that filters network traffic based on rules.

18. What is a proxy server? → Acts as an intermediary between clients and servers for caching and security.

19. Explain load balancing: → Distributes network traffic across multiple servers for efficiency.

20. What is QoS (Quality of Service)? → Prioritizes network traffic to ensure performance for critical applications.

21. What is a MAC address? → Unique hardware identifier assigned to network interfaces.

22. Difference between LAN, WAN, and MAN: → LAN covers local area; WAN covers wide area; MAN covers metropolitan area.

23. What is a VPN and how does it work? → Creates secure encrypted tunnels over public networks.

24. What is port forwarding? → Redirects communication requests from one port to another for remote access.

25. Difference between symmetric and asymmetric encryption: → Symmetric uses one key; asymmetric uses public and private keys.

CCNA (25 Questions)

1. What is Cisco IOS? → Cisco’s operating system for routers and switches.

2. Difference between enable mode and configuration mode: → Enable mode allows privileged commands; configuration mode allows device setup.

3. Purpose of show ip route command: → Displays routing table entries.

4. Difference between RIP, OSPF, and EIGRP: → RIP uses hop count; OSPF uses link state; EIGRP uses hybrid metrics.

5. Distance vector vs. link state protocols: → Distance vector shares routes with neighbors; link state shares topology.

6. Purpose of ACLs: → Control traffic flow and enhance security.

7. Standard vs. extended ACLs: → Standard filters by source IP; extended filters by source, destination, and protocol.

8. Function of ping and traceroute: → Ping tests connectivity; traceroute shows path to destination.

9. Difference between console, AUX, and VTY lines: → Console for local access; AUX for modem; VTY for remote access.

10. Purpose of copy running-config startup-config: → Saves current configuration to memory for reboot persistence.

11. Difference between static and dynamic NAT: → Static maps one‑to‑one; dynamic maps from a pool.

12. Purpose of show interfaces: → Displays interface status and statistics.

13. Difference between trunk and access ports: → Trunk carries multiple VLANs; access carries one VLAN.

14. Purpose of STP (Spanning Tree Protocol): → Prevents network loops in switches.

15. Broadcast vs. multicast vs. unicast: → Broadcast to all; multicast to group; unicast to one.

16. Purpose of HSRP: → Provides router redundancy for high availability.

17. IPv4 vs. IPv6 addressing in Cisco: → IPv6 uses longer addresses and supports auto‑configuration.

18. Purpose of reload command: → Restarts the device.

19. Router‑on‑a‑stick vs. inter‑VLAN routing: → Router‑on‑a‑stick uses one physical interface; inter‑VLAN uses multiple.

20. Purpose of show cdp neighbors: → Displays directly connected Cisco devices.

21. Layer 2 vs. Layer 3 switches: → Layer 2 switches use MAC; Layer 3 switches route using IP.

22. Purpose of DHCP snooping: → Prevents rogue DHCP servers.

23. Port security vs. MAC filtering: → Port security limits MACs per port; MAC filtering allows specific MACs.

24. Purpose of show running-config: → Displays current configuration.

25. Primary vs. secondary IP addresses: → Primary is main interface IP; secondary adds another subnet.

Hardware (25 Questions)

1. Main components of a computer system: → CPU, RAM, motherboard, storage, PSU, GPU, peripherals.

2. Difference between RAM and ROM: → RAM is volatile; ROM is permanent.

3. Difference between HDD and SSD: → HDD uses spinning disks; SSD uses flash memory.

4. Function of motherboard: → Connects and communicates between all components.

5. Difference between BIOS and UEFI: → UEFI is modern, graphical, and supports larger drives.

6. Purpose of PSU: → Converts AC to DC power for components.

7. Difference between input and output devices: → Input sends data to computer; output displays results.

8. Function of CPU: → Executes instructions and processes data.

9. Cache vs. main memory: → Cache is faster, smaller, and stores frequently used data.

10. Purpose of GPU: → Handles graphics and parallel processing.

11. Difference between SATA and NVMe drives: → SATA uses cables; NVMe connects directly to motherboard.

12. Purpose of NIC: → Enables network connectivity.

13. Difference between USB 2.0, 3.0, and Type‑C: → Speed and connector design; Type‑C is reversible.

14. Purpose of heat sinks and fans: → Dissipate heat from components.

15. Single‑core vs. multi‑core processors: → Multi‑core handles multiple tasks simultaneously.

16. Purpose of CMOS battery: → Maintains BIOS settings and clock.

17. Integrated vs. dedicated graphics: → Integrated shares system memory; dedicated has its own.

18. Purpose of RAID: → Combines drives for redundancy or performance.

19. Difference between DDR3, DDR4, DDR5 RAM: → Speed, voltage, and bandwidth improvements.

20. Purpose of POST: → Tests hardware during startup.

21. Difference between PCI and PCIe slots: → PCIe offers faster serial communication.

22. Purpose of sound card: → Converts digital audio to analog signals.

23. Difference between CRT and LCD monitors: → CRT uses cathode rays; LCD uses liquid crystals.

24. Purpose of thermal paste: → Improves heat transfer between CPU and cooler.

25. Wired vs. wireless peripherals: → Wired use cables; wireless use Bluetooth or RF.

Operating Systems (25 Questions)

1. Difference between Windows, Linux, and macOS: → Windows is proprietary; Linux is open‑source; macOS is Apple’s Unix‑based OS.

2. Purpose of an operating system: → Manages hardware, software, and user interaction.

3. Difference between 32‑bit and 64‑bit OS: → 64‑bit handles more memory and faster processing.

4. Kernel mode vs. user mode: → Kernel mode has full access; user mode is restricted.

5. Purpose of file system: → Organizes and manages data storage.

6. Difference between FAT32, NTFS, and ext4: → FAT32 is older; NTFS supports permissions; ext4 is Linux‑based.

7. Purpose of process scheduling: → Allocates CPU time to processes efficiently