N10-009 Study Guide — How to Pass Network+

IPv4 Subnetting

Subnetting is the skill that separates people who understand networking from people who just use it.

VLANs & Trunking

Without VLANs, every device on a switch is in the same broadcast domain.

OSI & TCP/IP Models

Every time you load a webpage, seven invisible layers of technology coordinate to make it happen and most people could not name three of them.

Ethernet & Switching

Ethernet is the technology that connects almost every wired device in the world.

IPv6

IPv4 has roughly 4.

NAT & PAT

Your home router gives your laptop a private IP address like 192.

DHCP & DNS

Two protocols make modern networks usable without any configuration from end users.

Wireless 802.11

Wi-Fi looks simple from the user side.

OSI Model

The OSI (Open Systems Interconnection) model is one of the highest-yield topics on the CompTIA Network+ N10-009 exam, appearing in questions across all five domains.

TCP/IP Model

The TCP/IP model is the practical framework that modern networks actually use, as opposed to the OSI model which is a theoretical reference.

Ports and Protocols

Port and protocol knowledge is one of the most heavily tested areas on CompTIA Network+ N10-009.

Network Devices

Identifying network devices, their functions, and their OSI layer is a foundational Network+ N10-009 topic.

Cloud Concepts

Cloud computing is explicitly tested on CompTIA Network+ N10-009 as part of Networking Concepts (Domain 1).

WAN Technologies

Wide Area Network (WAN) technologies connect geographically dispersed sites and are tested on CompTIA Network+ N10-009 across multiple domains.

Network Topologies

Network topology describes the physical or logical arrangement of network nodes and connections.

Cable Types

Cable types and connectors are directly tested on CompTIA Network+ N10-009, with questions asking you to identify the correct cable for a scenario, recognize connector types, and understand cable specifications.

Ethernet Standards

Ethernet is the dominant Layer 2 LAN technology, governed by the IEEE 802.

Bandwidth and Throughput

Understanding the difference between bandwidth, throughput, and latency is fundamental to network performance analysis and troubleshooting, both of which are tested throughout CompTIA Network+ N10-009.

Virtualization and SDN

Virtualization and Software-Defined Networking (SDN) are explicitly tested on CompTIA Network+ N10-009 as modern infrastructure concepts.

Network Segmentation

Network segmentation divides a network into smaller, isolated sections to improve security, performance, and manageability.

DNS Records

DNS (Domain Name System) record types are directly tested on CompTIA Network+ N10-009.

Subnetting

Subnetting is guaranteed to appear on CompTIA Network+ N10-009, typically as 3–5 questions requiring you to calculate network addresses, usable host ranges, broadcast addresses, and subnet masks from CIDR notation.

IPv6

IPv6 is tested on CompTIA Network+ N10-009 with increasing weight as IPv4 exhaustion drives adoption.

NAT Concepts

Network Address Translation (NAT) is a foundational concept tested on CompTIA Network+ N10-009 in both networking concepts and troubleshooting domains.

Routing Concepts

Routing concepts are central to CompTIA Network+ N10-009, appearing across networking concepts, implementation, and troubleshooting domains.

Switching Concepts

Switching concepts are core to CompTIA Network+ N10-009, covering how switches learn and forward frames, VLANs, spanning tree, and port-level security.

Wireless Standards

Wireless networking standards (IEEE 802.

TCP vs UDP

TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) are the two Transport layer protocols tested on CompTIA Network+ N10-009.

IoT and SCADA

IoT (Internet of Things) and SCADA/ICS (Supervisory Control and Data Acquisition / Industrial Control Systems) networks are explicitly listed in CompTIA Network+ N10-009 exam objectives under networking concepts and network security.

Routing Protocols

Routing protocols enable routers to dynamically share network reachability information, automatically adapting to topology changes.

Static Routing

Static routing is the simplest form of routing where network administrators manually define routes in the routing table.

VLAN Implementation

VLAN implementation is a core Network+ N10-009 topic spanning both networking concepts and implementation domains.

Spanning Tree

Spanning Tree Protocol (STP) prevents Layer 2 loops in switched networks with redundant paths.

EtherChannel

EtherChannel (Link Aggregation Group / LAG) bundles multiple physical Ethernet links between switches into a single logical link, increasing bandwidth and providing redundancy.

Wireless Implementation

Wireless network implementation covers the design and deployment of Wi-Fi infrastructure, including access point placement, controller architecture, and roaming.

AP Placement

Proper access point placement is critical for wireless network performance and coverage.

DHCP Implementation

DHCP (Dynamic Host Configuration Protocol) automatically assigns IP addresses and network configuration to clients.

DNS Implementation

DNS (Domain Name System) implementation encompasses how DNS servers are deployed, how zones are structured, how resolution works end-to-end, and how to configure DNS for reliability.

VPN Implementation

VPNs (Virtual Private Networks) create encrypted tunnels over public networks, enabling secure remote access and site-to-site connectivity.

Quality of Service

Quality of Service (QoS) mechanisms prioritize certain network traffic types to ensure critical applications receive the bandwidth, low latency, and low jitter they need.

Internet Connectivity

Internet connectivity options and the technologies that connect organizations to the internet are tested on CompTIA Network+ N10-009.

Network Hardening Basics

Network hardening involves securing network devices and infrastructure against attack.

Load Balancing

Load balancing distributes incoming network traffic across multiple servers to prevent any single server from becoming a bottleneck.

WLAN Configuration

WLAN (Wireless LAN) configuration covers the settings required to deploy and secure a wireless network.

Network Documentation

Network documentation is a fundamental Network Operations topic on CompTIA Network+ N10-009.

Network Monitoring

Network monitoring provides ongoing visibility into network health, performance, and security.

Performance Metrics

Measuring network performance enables proactive identification of issues before users are impacted.

High Availability

High availability (HA) ensures network services remain accessible despite component failures.

Disaster Recovery

Disaster recovery (DR) planning ensures organizations can restore network and IT services after a major disruption.

Change Management

Change management is a formal process for requesting, reviewing, approving, and documenting network changes.

Configuration Management

Configuration management ensures network device configurations are controlled, documented, backed up, and consistent with intended standards.

Remote Access Management

Remote access management covers how administrators securely access network devices and how users access corporate resources remotely.

Network Baseline

A network baseline documents normal performance levels across key metrics, providing a reference point for identifying deviations that indicate problems.

Software Updates

Keeping network device firmware and software current is a critical operational responsibility.

Packet Capture

Packet capture is the process of recording network traffic for analysis, security investigation, and troubleshooting.

Log Management

Log management involves collecting, storing, and analyzing log data from network devices, servers, and security systems.

Backup and Restore

Backup and restore strategies ensure that data and configurations can be recovered after failure or disaster.

Capacity Planning

Capacity planning ensures the network has sufficient resources to meet current and future demands.

Troubleshooting Tools

Network troubleshooting tools are directly tested on CompTIA Network+ N10-009 across the Operations and Troubleshooting domains.

Security Concepts

Security concepts underpin the entire Network Security domain of CompTIA Network+ N10-009 (20% of the exam).

Common Attacks

Identifying common network attacks is a major component of the Network+ N10-009 Security domain.

Firewall Types

Firewalls are the primary network security boundary control, and CompTIA Network+ N10-009 tests multiple firewall types, their capabilities, and appropriate use cases.

IDS and IPS

IDS (Intrusion Detection System) and IPS (Intrusion Prevention System) are security controls that monitor network traffic for malicious activity.

ACL Fundamentals

Access Control Lists (ACLs) are rule-based traffic filters applied to router and firewall interfaces to permit or deny traffic based on defined criteria.

Authentication Methods

Authentication verifies identity before granting network access.

Wireless Security

Wireless security is a major component of the Network+ N10-009 Security domain.

DHCP Snooping and DAI

DHCP snooping and Dynamic ARP Inspection (DAI) are Layer 2 security features that prevent common network attacks.

Vulnerability Scanning

Vulnerability scanning proactively identifies security weaknesses in network devices, servers, and applications before attackers can exploit them.

Patch Management

Patch management is the systematic process of keeping software and firmware current to address security vulnerabilities and software defects.

Zero Trust

Zero Trust is a security model that eliminates implicit trust based on network location — every access request must be verified regardless of where it originates.

Incident Response

Incident response is the structured process for detecting, containing, and recovering from security incidents.

Compliance Frameworks

Compliance frameworks define security standards and requirements that organizations must meet based on their industry, data types, and geographic location.

VPN Security

VPN security encompasses the protocols, encryption, and authentication mechanisms that protect VPN tunnels.

Physical Security

Physical security protects network infrastructure from physical access, theft, and tampering.

Network Hardening

Network hardening reduces attack surface by eliminating vulnerabilities and unnecessary services from network infrastructure.

Social Engineering

Social engineering exploits human psychology rather than technical vulnerabilities to gain unauthorized access or information.

Cloud Security

Cloud security applies security principles to cloud-hosted infrastructure, applications, and data.

Honeypot and Deception

Honeypots and deception technologies are security controls that detect attackers by luring them into interacting with fake, monitored systems.

Data Loss Prevention

Data Loss Prevention (DLP) systems detect and prevent unauthorized transmission of sensitive data outside the organization.

Troubleshooting Methodology

CompTIA's structured troubleshooting methodology is the highest-yield topic in the Network Troubleshooting domain (21% of the exam).

Physical Layer Issues

Physical layer (Layer 1) issues cause the most fundamental network problems — no link, intermittent connectivity, and high error rates.

Connectivity Troubleshooting

Connectivity troubleshooting is the most common network support task and is heavily tested throughout the CompTIA Network+ N10-009 Troubleshooting domain.

DNS Troubleshooting

DNS troubleshooting is directly tested on CompTIA Network+ N10-009.

DHCP Troubleshooting

DHCP troubleshooting is a core Network+ N10-009 skill tested in the Troubleshooting domain.

Wireless Troubleshooting

Wireless troubleshooting is a dedicated section of the CompTIA Network+ N10-009 Troubleshooting domain.

Performance Troubleshooting

Performance troubleshooting addresses slow network response, high latency, packet loss, and bandwidth issues that degrade application quality without completely breaking connectivity.

Routing Troubleshooting

Routing troubleshooting diagnoses connectivity failures caused by misconfigured routing tables, failed routing protocols, or incorrect static routes.

VLAN Troubleshooting

VLAN troubleshooting diagnoses connectivity failures caused by misconfigured VLANs, trunk ports, and native VLAN mismatches.

Firewall Troubleshooting

Firewall troubleshooting diagnoses connectivity failures caused by firewall rules blocking legitimate traffic.

VPN Troubleshooting

VPN troubleshooting diagnoses failures in both remote access VPNs (users connecting from home) and site-to-site VPNs (connecting offices).

Network Tools

Network diagnostic tools are tested throughout the CompTIA Network+ N10-009 Troubleshooting domain.

Cable Testing

Cable testing verifies the physical integrity and performance of network cables.

Cloud Troubleshooting

Cloud network troubleshooting addresses connectivity and performance issues specific to cloud-hosted infrastructure.

Network Protocols

Network protocols define the rules and formats that allow devices to communicate.

Multicast & Broadcast

Understanding unicast, multicast, and broadcast traffic types is fundamental to Network+ N10-009.

Media & Connectors

Network media and connectors are fundamental to the physical layer — everything else depends on the underlying cable or wireless medium carrying the signal.

Infrastructure Concepts

Network infrastructure encompasses the physical and logical components that make up a network — from the devices and cabling in a data center to the topology that connects remote sites.

Address Management

Network address management encompasses IPAM (IP Address Management), DHCP management, DNS integration, and subnetting practices that keep an IP space organized and scalable.

Switch Configuration

Switch configuration is central to CompTIA Network+ N10-009 Network Implementation domain.

Router Configuration

Router configuration implements the Layer 3 routing decisions that move traffic between networks.