1. Which layer of the OSI model is responsible for routing packets?
A) Data Link Layer
B) Transport Layer
C) Network Layer
D) Session Layer
✅ Answer: C) Network Layer
💡 Explanation: The Network Layer (Layer 3) handles logical addressing and routing of packets across networks.
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2. The maximum number of IP addresses in IPv4 is:
A) 2^16
B) 2^32
C) 2^64
D) 2^128
✅ Answer: B) 2^32
💡 Explanation: IPv4 uses 32-bit addresses, allowing 2^32 ≈ 4.3 billion unique addresses.
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3. Which protocol is used to assign IP addresses automatically?
A) DNS
B) FTP
C) DHCP
D) SNMP
✅ Answer: C) DHCP
💡 Explanation: DHCP (Dynamic Host Configuration Protocol) automatically assigns IP addresses to devices on a network.
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4. The ‘3-way handshake’ is associated with which protocol?
A) UDP
B) TCP
C) HTTP
D) ICMP
✅ Answer: B) TCP
💡 Explanation: TCP uses a 3-way handshake (SYN → SYN-ACK → ACK) to establish a reliable connection.
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5. Which of the following is a private IP address range?
A) 100.0.0.0 – 100.255.255.255
B) 192.168.0.0 – 192.168.255.255
C) 200.0.0.0 – 200.255.255.255
D) 210.0.0.0 – 210.255.255.255
✅ Answer: B) 192.168.0.0 – 192.168.255.255
💡 Explanation: Private IP ranges (RFC 1918): 10.x.x.x, 172.16-31.x.x, and 192.168.x.x.
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6. HTTPS uses which default port number?
A) 80
B) 21
C) 443
D) 8080
✅ Answer: C) 443
💡 Explanation: HTTPS (secure HTTP) uses port 443 by default, while HTTP uses port 80.
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7. Which device operates at both Layer 2 and Layer 3 of the OSI model?
A) Hub
B) Switch
C) Router
D) Layer 3 Switch
✅ Answer: D) Layer 3 Switch
💡 Explanation: Layer 3 switches combine switching (L2) and routing (L3) capabilities in one device.
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8. The DNS resolves:
A) MAC address to IP address
B) IP address to MAC address
C) Domain name to IP address
D) IP address to domain name
✅ Answer: C) Domain name to IP address
💡 Explanation: DNS (Domain Name System) translates human-readable domain names to IP addresses.
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9. Which protocol is connectionless and faster but less reliable?
A) TCP
B) FTP
C) UDP
D) SMTP
✅ Answer: C) UDP
💡 Explanation: UDP (User Datagram Protocol) is connectionless and does not guarantee delivery, making it faster.
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10. Subnetting is used to:
A) Increase internet speed
B) Divide a network into smaller sub-networks
C) Encrypt data
D) Monitor network traffic
✅ Answer: B) Divide a network into smaller sub-networks
💡 Explanation: Subnetting divides a large network into smaller, manageable sub-networks for efficiency and security.
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11. ARP stands for:
A) Address Resolution Protocol
B) Advanced Routing Protocol
C) Automated Route Processing
D) Application Routing Protocol
✅ Answer: A) Address Resolution Protocol
💡 Explanation: ARP maps an IP address to its corresponding MAC (physical) address on a local network.
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12. Which layer of OSI model does SSL/TLS operate?
A) Network Layer
B) Transport Layer
C) Presentation Layer
D) Session Layer
✅ Answer: C) Presentation Layer
💡 Explanation: SSL/TLS primarily operates at the Presentation Layer (Layer 6), handling encryption and decryption.
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13. What is the purpose of NAT (Network Address Translation)?
A) Assigns domain names
B) Allows multiple devices to share a single public IP address
C) Encrypts network traffic
D) Routes packets between networks
✅ Answer: B) Allows multiple devices to share a single public IP address
💡 Explanation: NAT translates private IP addresses to a public IP, allowing multiple devices to share one public IP.
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14. Bandwidth is measured in:
A) Hertz (Hz)
B) Bits per second (bps)
C) Bytes per minute
D) Watts
✅ Answer: B) Bits per second (bps)
💡 Explanation: Network bandwidth (data transfer capacity) is measured in bits per second (bps, Mbps, Gbps).
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15. Which topology is most fault-tolerant?
A) Bus Topology
B) Star Topology
C) Ring Topology
D) Mesh Topology
✅ Answer: D) Mesh Topology
💡 Explanation: Mesh topology provides multiple redundant paths between nodes, making it the most fault-tolerant.
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16. The port number for SSH is:
A) 22
B) 23
C) 25
D) 443
✅ Answer: A) 22
💡 Explanation: SSH (Secure Shell) uses port 22 for encrypted remote login and command execution.
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17. SMTP is used for:
A) Receiving emails
B) Sending emails
C) Browsing the web
D) File transfer
✅ Answer: B) Sending emails
💡 Explanation: SMTP (Simple Mail Transfer Protocol) is used for sending email messages between servers.
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18. Which protocol does the ‘ping’ command use?
A) TCP
B) UDP
C) ICMP
D) ARP
✅ Answer: C) ICMP
💡 Explanation: The ping command uses ICMP (Internet Control Message Protocol) Echo Request and Echo Reply messages.
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19. A VLAN is used to:
A) Increase network speed
B) Logically segment a network without physical separation
C) Assign IP addresses
D) Monitor packets
✅ Answer: B) Logically segment a network without physical separation
💡 Explanation: VLANs create logical network segments on the same physical infrastructure for security and organization.
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20. Which wireless standard provides maximum theoretical speed of 9.6 Gbps?
A) Wi-Fi 5 (802.11ac)
B) Wi-Fi 6 (802.11ax)
C) Wi-Fi 4 (802.11n)
D) Bluetooth 5.0
✅ Answer: B) Wi-Fi 6 (802.11ax)
💡 Explanation: Wi-Fi 6 (802.11ax) supports a theoretical maximum throughput of up to 9.6 Gbps.
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