DATA COMMUNICATIONS & COMPUTER NETWORKING 300-Exam Questions • Original Questions • Answers Marked • Explanations Included

DATA COMMUNICATIONS & COMPUTER NETWORKING 300-Exam Questions • Original Questions • Answers Marked • Explanations Included Comprehensive Networking Review Switching • Routing • TCP/IP • OSI • Addressing • Wireless • Security • Cloud • Virtualization • Network Services • Troubleshooting • Disaster Recovery    1. A network administrator wants to divide one physical switch into separate logical broadcastdomains. Which technology should be used? A. VLANs B. NAT C. DNS D. FTP Correct Answer: A. VLANs Rationale: VLANs logically separate a switched network into different broadcast domains. 2. Which protocol is commonly used to automatically discover a host's IP configuration from a DHCPserver? A. DHCP B. SMTP C. SSH D. SNMP Correct Answer: A. DHCP Rationale: DHCP provides automatic IP configuration to network clients. 3. A packet has a destination IP address outside the local subnet. Where does a typical host send thepacket first? A. Default gateway B. Local printer C. DNS server D. Switch management port Correct Answer: A. Default gateway Rationale: Traffic for remote networks is normally sent to the configured default gateway. 4. Which device learns source MAC addresses and stores them in a forwarding table? A. Switch B. Router C. Modem D. Firewall only Correct Answer: A. Switch Rationale: Ethernet switches learn source MAC addresses to build their forwarding tables. 5. Which protocol provides reliable, ordered delivery at the transport layer? A. TCP B. UDP C. IP D. ARP Correct Answer: A. TCP Rationale: TCP provides reliable, ordered, connection-oriented transport. 6. Which protocol is generally connectionless and has lower transport overhead than TCP? A. UDP B. TCP C. HTTPS D. SSH Correct Answer: A. UDP Rationale: UDP is connectionless and does not provide TCP-style reliability mechanisms. 7. A user can ping a server by IP address but cannot open it by hostname. Which service should beinvestigated? A. DNS B. DHCP C. NTP D. SMTP Correct Answer: A. DNS Rationale: Successful IP connectivity with failed name resolution points toward DNS. 8. Which technology allows private IPv4 addresses to communicate through a shared publicaddress? A. NAT B. VLAN C. ARP D. SNMP Correct Answer: A. NAT Rationale: NAT translates private addresses to public addresses when communicating externally. 9. Which IPv4 address is from the loopback range? A. 127.0.0.1 B. 192.168.1.1 C. 10.1.1.1 D. 8.8.8.8 Correct Answer: A. 127.0.0.1 Rationale: 127.0.0.1 is the commonly used IPv4 loopback address. 10. What is the primary purpose of a subnet mask? A. Identify the network and host portions of an IPv4 address B. Encrypt packets C. Name a wireless network D. Identify an application Correct Answer: A. Identify the network and host portions of an IPv4 address Rationale: A subnet mask indicates which IPv4 bits represent the network and which represent the host. 11. Which protocol resolves a hostname to an IP address? A. DNS B. ARP C. DHCP D. ICMP Correct Answer: A. DNS Rationale: DNS provides hostname-to-IP address resolution. 12. Which protocol resolves a local IPv4 address to a MAC address? A. ARP B. DNS C. HTTP D. SMTP Correct Answer: A. ARP Rationale: ARP is used on IPv4 Ethernet networks to discover the MAC address associated with a local IP address. 13. Which protocol is primarily used for diagnostic echo testing? A. ICMP B. SMTP C. FTP D. IMAP Correct Answer: A. ICMP Rationale: Ping uses ICMP echo messages to test reachability. 14. Which command-line utility commonly displays the route packets take to a destination? A. traceroute/tracert B. format C. mkdir D. passwd Correct Answer: A. traceroute/tracert Rationale: Traceroute or tracert identifies routing hops toward a destination. 15. Which service is designed to synchronize clocks across networked systems? A. NTP B. DNS C. DHCP D. FTP Correct Answer: A. NTP Rationale: Network Time Protocol synchronizes system clocks. 16. Which protocol is used to transfer files securely over an SSH-based connection? A. SFTP B. HTTP C. SMTP D. ARP Correct Answer: A. SFTP Rationale: SFTP provides file transfer through the SSH protocol. 17. Which protocol is normally used to submit outgoing email? A. SMTP B. IMAP C. DNS D. DHCP Correct Answer: A. SMTP Rationale: SMTP is used for email submission and transfer. 18. Which protocol is designed for retrieving and synchronizing email stored on a server? A. IMAP B. ARP C. ICMP D. SNMP Correct Answer: A. IMAP IMAP maintains synchronization with server-side mailboxes. 19. Which application-layer protocol is commonly associated with secure remote administration? A. SSH B. HTTP C. SMTP D. DNS Correct Answer: A. SSH Rationale: SSH provides encrypted remote administration. 20. What does HTTPS add to ordinary HTTP? A. TLS-based protection B. A larger IP address C. A new MAC address D. A physical cable Correct Answer: A. TLS-based protection Rationale: HTTPS uses TLS to protect HTTP communications.