50 Free CompTIA Network+ Practice Questions (N10-009)

Answer: b) Session (Layer 5)

Explanation: The Session layer establishes, maintains, and terminates sessions between communicating applications. It manages dialog control (half-duplex vs full-duplex) and checkpointing.

Answer: b) TCP

Explanation: TCP (Transmission Control Protocol) provides reliable, connection-oriented communication with error checking, flow control, and acknowledgment. UDP is connectionless and faster but unreliable.

Answer: c) 255.255.255.0

Explanation: Class C addresses have default subnet mask 255.255.255.0 (/24). Class A = 255.0.0.0 (/8), Class B = 255.255.0.0 (/16).

Answer: d) All of the above

Explanation: RFC 1918 defines three private IP ranges: 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16. These addresses are not routable on the public internet.

Answer: a) TCP is reliable and connection-oriented; UDP is connectionless and faster

Explanation: TCP provides reliability through acknowledgments, retransmission, and sequencing. UDP provides faster but unreliable delivery, making it suitable for streaming and real-time applications.

Answer: b) ARP

Explanation: ARP (Address Resolution Protocol) resolves IP addresses to MAC addresses on a local network. Reverse ARP (RARP) does the opposite. DNS resolves hostnames to IP addresses.

Answer: c) 127.0.0.1

Explanation: 127.0.0.1 is the IPv4 loopback address (localhost). It points back to the local machine. For IPv6, the loopback address is ::1.

Answer: b) fe80::1

Explanation: fe80::1 is a valid IPv6 link-local address. IPv6 uses 128-bit hexadecimal notation with colons. Options a is IPv4, c has invalid octet (256), d has too many octets.

Answer: b) 53

Explanation: DNS (Domain Name System) uses port 53 for both TCP and UDP. UDP is used for standard queries; TCP is used for zone transfers and large responses.

Answer: a) A method for describing IP addresses and subnet masks compactly (e.g., /24)

Explanation: CIDR (Classless Inter-Domain Routing) notation expresses the subnet mask as the number of network bits (e.g., 192.168.1.0/24 means 255.255.255.0).

Answer: b) DHCP

Explanation: DHCP (Dynamic Host Configuration Protocol) automatically assigns IP addresses, subnet masks, default gateways, and DNS servers to devices on a network.

Answer: b) Translating private IP addresses to public IP addresses

Explanation: NAT allows multiple devices on a private network to share a single public IP address for internet access. It conserves public IPv4 addresses.

Answer: b) Switch

Explanation: Switches operate at Layer 2 (Data Link), forwarding frames based on MAC addresses. Routers operate at Layer 3 (IP). Hubs operate at Layer 1 (signal repeating).

Answer: a) Virtual Local Area Network

Explanation: A VLAN creates logically separate networks on the same physical switch, isolating traffic and improving security and performance without additional hardware.

Answer: b) 802.11ac (WiFi 5)

Explanation: 802.11ac (WiFi 5) operates on 5 GHz only, with speeds up to 1.3 Gbps. WiFi 4 (802.11n) works on both 2.4/5 GHz up to 600 Mbps. WiFi 6 (802.11ax) is faster.

Answer: c) RIP

Explanation: RIP (Routing Information Protocol) uses hop count as its metric (max 15 hops). OSPF uses cost (bandwidth), EIGRP uses a composite metric, BGP uses path attributes.

Answer: b) The router that forwards traffic from a local network to other networks

Explanation: The default gateway is the router IP that devices use to send traffic destined for networks outside their local subnet.

Answer: b) Twisted pair (UTP/STP)

Explanation: Twisted pair copper cable (Cat5e, Cat6, Cat6a) is the most common Ethernet cabling, using RJ45 connectors. Fiber optic is used for long distances and higher bandwidth.

Answer: b) 100 meters

Explanation: The maximum length for twisted pair Ethernet (Cat5e, Cat6, Cat6a) is 100 meters (328 feet) before signal degradation requires a repeater or switch.

Answer: b) Electrical power and data over a single Ethernet cable

Explanation: PoE delivers power (up to 15.4W for PoE, 30W for PoE+) along with data on Ethernet cables, eliminating the need for separate power cabling for devices like IP cameras, phones, and access points.

Answer: b) Router

Explanation: A router connects different networks and forwards packets based on destination IP addresses using routing tables. Switches forward frames within the same network.

Answer: b) An all-in-one device combining router, switch, wireless AP, and firewall for small networks

Explanation: A SOHO router integrates multiple functions: router (NAT), switch (ports), wireless access point (WiFi), and firewall in one device for small office/home use.

Answer: b) Observing network performance, detecting issues, and ensuring availability

Explanation: Network monitoring continuously observes network infrastructure (bandwidth, device health, error rates) to detect and alert on issues before they impact users.

Answer: b) SNMP

Explanation: SNMP (Simple Network Management Protocol) is used to monitor and manage network devices (switches, routers, printers) by collecting metrics and receiving alerts.

Answer: b) Recording network topology, configurations, IP schemes, and procedures

Explanation: Network documentation (diagrams, IP address schemas, device configs, SOPs) is essential for troubleshooting, change management, onboarding, and disaster recovery.

Answer: b) A diagram showing data flow and network structure (IPs, VLANs, protocols)

Explanation: A logical topology diagram shows how data flows on the network — IP addressing, VLANs, routing protocols, and subnets. A physical diagram shows cable paths and device locations.

Answer: b) Defining guaranteed uptime, response times, and performance metrics

Explanation: An SLA with an ISP defines guaranteed service levels including uptime percentage, latency, packet loss, and response times for support.

Answer: b) Documented procedures for restoring network operations after a major failure

Explanation: A DRP defines procedures to restore network infrastructure after a disaster (natural disaster, fire, major equipment failure) including backup sites, restoration priorities, and recovery time objectives.

Answer: b) The network is designed to minimize downtime through redundancy and failover

Explanation: High availability uses redundant components (power supplies, links, devices) and failover mechanisms to ensure network uptime when individual components fail.

Answer: b) A structured approach to planning, approving, implementing, and reviewing network changes

Explanation: Change management ensures network changes (config updates, hardware replacements, firmware upgrades) are reviewed, approved, tested, and documented to minimize risk.

Answer: c) Firewall

Explanation: A firewall filters network traffic based on security rules. Stateful firewalls track connection state and allow return traffic automatically.

Answer: a) Stateful tracks connection state; stateless filters each packet independently

Explanation: Stateful firewalls maintain a connection table and allow return traffic automatically. Stateless firewalls (ACLs) examine each packet in isolation without connection context.

Answer: b) IPsec

Explanation: IPsec (Internet Protocol Security) is a common VPN protocol for site-to-site connections. It provides encryption and authentication at the IP layer.

Answer: b) A list of rules that permit or deny traffic on a router or switch

Explanation: ACLs on routers and switches filter traffic based on source/destination IP addresses, port numbers, and protocols. They're a basic form of stateless firewall.

Answer: b) Dividing a network into smaller parts to isolate traffic and improve security

Explanation: Network segmentation (using VLANs, subnets, firewalls) isolates different network zones (guest vs corporate, DMZ vs internal) to contain security breaches and control access.

Answer: b) A network segment that hosts public-facing services and isolates them from the internal network

Explanation: A DMZ sits between the internet and the internal network, hosting public services (web servers, email servers, DNS) to prevent direct access to internal resources.

Answer: b) Phishing

Explanation: Phishing uses deceptive emails (appearing to be from trusted sources) to trick recipients into revealing credentials or clicking malicious links. It's a social engineering attack.

Answer: b) Identify the problem

Explanation: The 7-step troubleshooting process: 1) Identify the problem, 2) Establish a theory of probable cause, 3) Test the theory, 4) Establish a plan of action, 5) Implement the solution, 6) Verify functionality, 7) Document findings.

Answer: b) ping

Explanation: ping sends ICMP Echo Request packets to a target IP/hostname and waits for Echo Reply, measuring round-trip time and packet loss.

Answer: b) tracert (or traceroute)

Explanation: tracert (Windows) or traceroute (Linux/macOS) shows each hop (router) along the path to a destination, including IP addresses and round-trip times.

Answer: b) ipconfig

Explanation: ipconfig (Windows) displays IP address, subnet mask, default gateway, and DNS servers. Linux/macOS uses ifconfig or ip addr.

Answer: c) netstat

Explanation: netstat displays active TCP/UDP connections, listening ports, routing tables, and network statistics. Useful for identifying suspicious connections.

Answer: b) nslookup (or dig)

Explanation: nslookup and dig are DNS troubleshooting tools that query DNS servers for record types (A, AAAA, MX, CNAME, NS, etc.).

Answer: b) The destination did not respond within the timeout period (could be down, blocked by firewall, or network issue)

Explanation: Request timed out means the source didn't receive an ICMP Echo Reply within the timeout period. This could be because the host is down, a firewall is blocking ICMP, or there's a network problem.

Answer: a) Wireshark

Explanation: Wireshark is a packet analyzer that captures and inspects network traffic in detail, showing protocol headers, payloads, and conversations.

Answer: b) The device couldn't reach a DHCP server and assigned itself a link-local address

Explanation: APIPA (Automatic Private IP Addressing) assigns 169.254.x.x when DHCP fails. It allows local communication but not internet access.

Answer: b) nmap

Explanation: nmap (Network Mapper) scans hosts and ports to discover open ports, running services, and operating systems. It's used for security assessment and network discovery.

Answer: b) Signal interference, bad cable, failing hardware, or overloaded network

Explanation: Intermittent connectivity is often caused by physical issues (bad cable, loose connector, interference), failing hardware (NIC, switch port), or bandwidth saturation.

Answer: b) The local router has no route to the destination network

Explanation: "Destination host unreachable" means the local router doesn't have a route to the destination network in its routing table. This is different from "Request timed out."

Answer: b) Application, Presentation, Session, Transport, Network, Data Link, Physical

Explanation: The OSI model layers from top to bottom: Application (7), Presentation (6), Session (5), Transport (4), Network (3), Data Link (2), Physical (1). Mnemonic: "All People Seem To Need Data Processing."