CompTIA Network+ (N10-009) study guide

How to use this guide

What to focus on:

• OSI and TCP/IP models, and which layer a given problem or device belongs to
• IPv4 and IPv6 addressing, subnetting, CIDR, public versus private ranges
• Ports, protocols and traffic types: unicast, multicast, anycast, broadcast
• Cloud and datacentre concepts: NFV, VPC, IaaS and SaaS connectivity models

What to focus on:

• Routing technologies and protocols: static, OSPF, EIGRP, BGP, and route selection
• Switching: VLANs, trunking, spanning tree, link aggregation, port mirroring
• Wireless standards, frequencies, channels, antenna types and site survey basics
• Physical installation: cable and connector types, transceivers, and the right media for a run

What to focus on:

• Documentation that matters: physical and logical diagrams, IPAM, baselines, lifecycle records
• High availability and disaster recovery: RTO, RPO, MTTR, MTBF, failover and redundancy
• Monitoring with SNMP, syslog, flow data, and reading performance metrics
• Change and configuration management, and safe rollback

What to focus on:

• The CIA triad, defence in depth, zero trust and least privilege as applied to networks
• Common attacks: DoS and DDoS, VLAN hopping, ARP and DNS poisoning, rogue access points
• Hardening: port security, 802.1X, MAC filtering, disabling unused services and ports
• Remote access and segmentation: VPN types, IPsec, site-to-site versus client, DMZ and screened subnets

What to focus on:

• Apply CompTIA's troubleshooting methodology in its published order, every time
• Cable and physical faults: attenuation, crosstalk, interference, incorrect pinout, duplex mismatch
• Command-line tools and what each proves: ping, traceroute, nslookup and dig, ipconfig and ifconfig, netstat, tcpdump
• Service issues: DHCP scope exhaustion, DNS resolution failures, routing loops, misconfigured ACLs

Common mistakes

• ✕Memorising port numbers and stopping there. The exam asks which protocol fits a scenario far more often than it asks for a number in isolation.
• ✕Leaving subnetting until the end. It underpins both the concepts and the troubleshooting domains, and it is the skill that most needs practice rather than reading.
• ✕Skipping the troubleshooting methodology because it looks like filler. It is examined as an ordered process, and questions turn on which step comes next.
• ✕Underrating operations. Documentation, monitoring and disaster-recovery metrics are 19% of the exam and the terminology is precise: RTO and RPO are not interchangeable.
• ✕Practising only multiple-choice. The performance-based questions come first and can swallow the clock if they are the first ones you have ever seen.

Exam-day tips

• ✓Skip the performance-based questions on the first pass and return with the time you have left. They are worth more, and they are also where people strand themselves.
• ✓Write out the subnetting reference you rely on in the first minute, on the board or its digital equivalent.
• ✓Name the OSI layer before choosing a tool. Most troubleshooting items resolve cleanly once the layer is settled.
• ✓Watch the scope words in the stem. FIRST, BEST and MOST likely change which of several correct-looking answers is the right one.
• ✓Answer everything. There is no penalty for a wrong answer and unanswered questions are marked incorrect.

How to know you’re ready

One good practice score can be luck. What counts is scoring at or above the real pass mark (720 on a 100 to 900 scale) across several full-length sets in a row, with no single domain trailing far behind the others. Kwizza tracks your per-domain readiness automatically as you practice.