CompTIA Network+ (N10-009) Study Guide: Complete Exam Prep

What Is CompTIA Network+?

CompTIA Network+ (N10-009) is a vendor-neutral networking certification that validates your ability to configure, manage, and troubleshoot wired and wireless networks. It's the industry standard for foundational networking knowledge.

Who should take it? Help desk technicians, network support specialists, and IT professionals moving into networking roles. CompTIA recommends having A+ or equivalent experience first.

Exam details:

• 90 multiple-choice and performance-based questions
• 90 minutes
• $358 USD
• Passing score: 720/900

The 5 Exam Domains

1. Networking Fundamentals (20%)

Master OSI model layers (especially the difference between Layer 2 switching and Layer 3 routing), TCP/IP protocols (TCP vs UDP, port numbers), subnetting basics (CIDR notation, VLSM), and IPv4 vs IPv6 addressing.

2. Network Implementations (18%)

Focus on Ethernet standards (802.3 series), cabling types (Cat5e, Cat6, Cat6a, fiber), wireless standards (802.11a/b/g/n/ac/ax — know speeds and frequencies), and switching concepts (VLANs, trunking, STP, link aggregation).

3. Network Operations (19%)

This domain covers documentation (logical vs physical diagrams), disaster recovery (backup types, RPO/RTO), business continuity (high availability, load balancing), and network monitoring (SNMP, syslog, NetFlow, sFlow).

4. Network Security (19%)

Know firewall types (stateless vs stateful), VPN protocols (IPSec, SSL/TLS, WireGuard), access control (802.1X, NAC), common attacks (DoS/DDoS, MITM, ARP spoofing), and security appliances (IDS/IPS, WAF).

5. Network Troubleshooting (24%)

The largest domain. Follow the CompTIA troubleshooting methodology:

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 full functionality
7. Document findings

Common troubleshooting scenarios include DNS resolution failures, DHCP issues, connectivity loss, slow performance, and wireless interference.

Subnetting: The Make-or-Break Skill

Subnetting appears throughout the exam. Master these calculations:

• Classful ranges (Class A: 1-126, Class B: 128-191, Class C: 192-223)
• Private ranges (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16)
• CIDR notation — know that /24 = 256 addresses, /25 = 128, /26 = 64, etc.
• Number of hosts per subnet = 2^(32 - CIDR) - 2

Study Approach: 8-12 Weeks

Week	Focus
1-2	OSI model, TCP/IP, port numbers, subnetting basics
3-4	Cabling, wireless, Ethernet, switching fundamentals
5-6	Routing protocols (OSPF, EIGRP, BGP — just basics), VLANs
7-8	Network security, firewalls, VPNs
9-10	Network operations, monitoring, documentation
11-12	PBQ practice, timed mock exams, weak area review

Start Practicing

Ready to test your networking knowledge? Try Certeli's CompTIA Network+ practice questions with detailed explanations for every answer.