Interview Questions - 2

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Networking

1. Difference between Hub, Switch, and Router

  • Hub: Sends data to all devices (broadcast). Example: If PC1 sends a file, all PCs receive it, even if only PC2 needs it.

  • Switch: Sends data only to the destination MAC. Example: PC1 → PC2 directly, no unnecessary traffic.

  • Router: Connects different networks. Example: Your home router connects LAN to the internet.

2. OSI Model and Layers Seven layers:

  1. Physical (cables, signals)

  2. Data Link (MAC addresses, Ethernet)

  3. Network (IP addressing, routing)

  4. Transport (TCP/UDP, reliability)

  5. Session (manages sessions)

  6. Presentation (encryption, compression)

  7. Application (user interface, HTTP, SMTP) Example: Sending an email uses all layers.

3. TCP vs UDP

  • TCP: Reliable, connection‑oriented. Example: Web browsing, email.

  • UDP: Fast, connectionless. Example: Streaming, gaming.

4. IP Address Classes & Subnetting

  • Class A: 1–126, large networks.

  • Class B: 128–191, medium.

  • Class C: 192–223, small. Subnetting: Divides a network into smaller parts. Example: Splitting 192.168.1.0/24 into two /25 subnets.

5. NAT (Network Address Translation) Converts private IPs to public. Example: 50 PCs in office share one public IP to access internet.

6. VLANs (Virtual LANs) Logical segmentation. Example: HR and Finance on separate VLANs for security.

7. Static vs Dynamic Routing

  • Static: Manual, stable. Example: Small office with fixed routes.

  • Dynamic: Auto‑updates. Example: ISP backbone using OSPF.

8. ARP (Address Resolution Protocol) Maps IP → MAC. Example: PC1 wants to talk to PC2 (192.168.1.10), ARP finds its MAC.

9. Bandwidth vs Latency

  • Bandwidth is the maximum amount of data that can be transmitted over a network connection in a given time. Measured in bits per second (bps), commonly Mbps or Gbps. (e.g., 100 Mbps).

  • Latency is the time delay between sending a request and receiving a response in a network. Measured in milliseconds (ms). (e.g., 50 ms ping).

  • Example: High bandwidth but high latency = slow gaming response.

10. Packet Switching Data split into packets. Example: Sending a video file, packets may take different routes but reassemble at destination.

11. Firewall Filters traffic. Example: Blocks port 23 (Telnet) for security.

12. Proxy Server Acts as middleman. Example: Company proxy caches websites to save bandwidth.

13. Load Balancing Distributes traffic. Example: A website uses 3 servers; load balancer sends users evenly.

14. IANA Manages IP addresses globally. Example: Assigns IPv4/IPv6 ranges to regions.

15. MAC Address Unique hardware ID. Example: 00:1A:2B:3C:4D:5E identifies a NIC.

16. LAN vs WAN vs MAN

  • LAN: Office network.

  • MAN: City‑wide (ISP metro).

  • WAN: Internet.

17. VPN Encrypted tunnel. Example: Employee connects securely to office network from home.

Hardware & OS

18. Main Components of Computer CPU, RAM, Motherboard, Storage, PSU, GPU, NIC, peripherals.

19. RAM vs ROM

  • RAM: Temporary, volatile. Example: Running apps.

  • ROM: Permanent. Example: BIOS firmware.

20. HDD vs SSD

  • HDD: Mechanical, slower. Example: 1 TB HDD.

  • SSD: Flash, faster. Example: 512 GB NVMe SSD.

21. BIOS vs UEFI

  • BIOS: Legacy, text‑based.

  • UEFI: Modern, supports >2 TB drives, graphical. Example: Secure Boot in UEFI.

22. NIC (Network Interface Card) Provides network connectivity. Example: Ethernet card in desktop.

23. Cache vs Main Memory

  • Cache: Faster, smaller. Example: CPU L1 cache.

  • RAM: Larger, slower. Example: 8 GB DDR4.

24. Dynamic Storage Systems Dynamic disks allow spanning/mirroring. Example: Two disks combined into one volume.

25. IPv4 vs IPv6

  • IPv4: 32‑bit, 4.3 billion addresses. Example: 192.168.1.1.

  • IPv6: 128‑bit, huge space. Example: 2001:db8::1.

Office 365 & Email Systems

26. Office 365 vs Traditional Office

  • Office 365: Cloud, subscription, collaboration.

  • Traditional: Local install, one‑time purchase. Example: Office 365 includes Teams, SharePoint.

27. OneDrive Role Cloud storage. Example: Save Word file, access from mobile.

28. Outlook & Exchange Integration Outlook = client, Exchange = server. Example: Outlook syncs mailbox from Exchange.

29. Multiple Outlook Profiles Control Panel → Mail → Add Profile. Example: Work + Personal accounts.

30. Outlook .PST File Local storage of emails. Example: Archive old emails.

31. Troubleshooting Outlook Connectivity Check internet, server settings, firewall, repair profile. Example: Outlook stuck in “Disconnected”.

32. Zoho Mail vs Outlook Zoho: Web‑based, CRM integration. Outlook: Rich client, Exchange integration.

33. Zoho Tools in Email Zoho CRM, Projects, Docs. Example: Sales team uses Zoho Mail + CRM.

34. Office 365 Collaboration Teams (chat/video), SharePoint (docs), OneDrive (files). Example: Team edits Excel in real‑time.

35. Securing Office 365 Accounts Enable MFA, conditional access, anti‑phishing. Example: Block login from unknown country.

Scenario‑Based Networking

36. LAN works but no Internet Check gateway, DNS, NAT. Example: Router misconfigured.

37. Limited Connectivity DHCP failure, IP conflict, bad cable. Example: Wrong IP assigned.

38. Ping Gateway but not Websites DNS issue. Example: DNS server unreachable.

39. DNS Queries Timing Out Check DNS server, firewall, cache. Example: ISP DNS down.

40. Broadcast Storm Mitigation Enable STP, VLANs, port security. Example: Loop in switch causes storm.

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