CompTIA Network+ (N10-009) — the full course

Every lesson and every lab is free to read, mapped one-to-one to CompTIA’s published exam objectives. The paid tier adds the 500-question exam simulator; nothing is taken away from the free course to make room for it.

Prefer a book? The 500-question practice-test book is on Amazon in paperback, and as an ebook on Google Play.

Prefer timed practice exams on Udemy? The 500 questions from this course’s bank are there as timed practice tests: see the Udemy course (launch price until 16 Nov 2026).

Free for the first 100 learners this month: take the same Udemy practice tests free, until 21 Nov 2026 or until the places are taken.

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10 lessons end with a short “try it” on a real Linux machine — several networked hosts, in fact — that runs in your browser and checks each step, and the Linux sandbox gives you that machine with no task at all.

44written lessons

74hands-on labs

62hours of lab work

44audio episodes

500practice questions

Start with lesson 1 — The OSI model and how data is encapsulated Exam simulator

Jump to a domain: 1. Networking Concepts · 2. Network Implementation · 3. Network Operations · 4. Network Security · 5. Network Troubleshooting

What the exam weighs

Domain	Share of the exam	Lessons here
1. Networking Concepts	23%	14
2. Network Implementation	20%	7
3. Network Operations	19%	9
4. Network Security	14%	5
5. Network Troubleshooting	24%	7

The curriculum

1. Networking Concepts 23% of the exam

01 The OSI model and how data is encapsulated objective 1.1 part single audio episode
- Measure what encapsulation costs you applied · 40 min
- See all four headers in one captured packet short · 25 min
02 Topologies, architectures and network types objective 1.6 part single audio episode
- Trace a three-tier design onto a real path applied · 45 min
- Find the broadcast domain boundaries in your own lab short · 30 min
03 Copper and fibre transmission media objective 1.5 part 1 of 2 audio episode
- Read what the NIC knows about the cable short · 25 min
04 Transceivers, connectors and cable standards objective 1.5 part 2 of 2 audio episode
- Build a link budget and decide go or no-go applied · 40 min
- Match five scenarios to the right optic short · 25 min
05 Routers, switches, firewalls and other appliances objective 1.2 part 1 of 2 audio episode
- Put a load balancer in front of two real servers short · 45 min
06 Network applications, functions and services objective 1.2 part 2 of 2 audio episode
- Prove why VoIP needs different treatment from a file copy applied · 45 min
- Watch a VPN change what the network can see short · 40 min
07 The ports and protocols you have to know cold objective 1.4 part 1 of 2 audio episode try it
- Identify seven services from their traffic alone short · 35 min
08 Unicast, broadcast, multicast and anycast objective 1.4 part 2 of 2 audio episode try it
- Break a link with the wrong MTU and then find it applied · 50 min
- Send one packet to four kinds of destination short · 30 min
09 IPv4 addressing, classes and private ranges objective 1.7 part 1 of 2 audio episode try it
- Classify twelve addresses on sight short · 25 min
10 Subnetting in practice objective 1.7 part 2 of 2 audio episode try it
- Re-subnet your lab and watch the mask decide everything applied · 50 min
- Subnet under exam time pressure short · 40 min
11 Cloud networking: VPCs, gateways and NFV objective 1.3 part 1 of 2 audio episode
- Design a VPC on paper and defend every subnet short · 40 min
12 Cloud service and deployment models objective 1.3 part 2 of 2 audio episode
- Size a hybrid connection and cost the alternatives applied · 45 min
- Draw the responsibility line for six services short · 30 min
13 SDN, SD-WAN and infrastructure as code objective 1.8 part 1 of 2 audio episode
- Separate the control plane from the data plane by hand short · 35 min
14 IaC practices and the IPv6 transition objective 1.8 part 2 of 2 audio episode
- Run dual stack and prove which one the host prefers applied · 45 min
- Domain 1 capstone — design a branch office from nothing capstone · 120 min
- Read and write IPv6 addresses correctly short · 30 min

2. Network Implementation 20% of the exam

01 Switching fundamentals and MAC learning objective 2.2 part 1 of 2 audio episode try it
- Watch a switch learn, age out and flood short · 35 min
02 VLANs, trunking and spanning tree objective 2.2 part 2 of 2 audio episode try it
- Create a loop, watch it hurt, then let STP fix it applied · 50 min
- Build two VLANs on one wire and read the tag short · 45 min
03 Routing fundamentals and the routing table objective 2.1 part 1 of 2 audio episode try it
- Make the router choose between four routes short · 40 min
04 Dynamic routing protocols and route selection objective 2.1 part 2 of 2 audio episode
- Configure NAT and watch the translation table applied · 45 min
- Bring up OSPF and watch it converge short · 50 min
05 Wireless standards and RF fundamentals objective 2.3 part 1 of 2 audio episode
- Survey the spectrum you are sitting in short · 35 min
06 Deploying and securing wireless networks objective 2.3 part 2 of 2 audio episode
- Produce a coverage map from measurements you took applied · 60 min
- Domain 2 capstone — implement the branch you designed capstone · 150 min
- Compare four wireless security modes on one network short · 40 min
07 Physical installations, power and environment objective 2.4 part single audio episode
- Terminate, label and document a patch run applied · 60 min
- Plan a rack and prove the power and cooling work short · 40 min

3. Network Operations 19% of the exam

01 DHCP and dynamic address assignment objective 3.4 part 1 of 3 audio episode
- Watch DORA happen, then break it short · 45 min
02 DNS in operation objective 3.4 part 2 of 3 audio episode
- Walk a name from the root down short · 35 min
03 DNS zones, resolution and time services objective 3.4 part 3 of 3 audio episode
- Diagnose four DNS faults from their symptoms applied · 50 min
- Build a forward and reverse zone that agree short · 45 min
04 Monitoring a network and reading its signals objective 3.2 part 1 of 2 audio episode
- Take a baseline you can actually compare against short · 45 min
05 SNMP, flow data and logging objective 3.2 part 2 of 2 audio episode
- Centralise logs and find one event across three hosts applied · 50 min
- Poll a device with SNMP and read the OID short · 40 min
06 Documentation, diagrams and asset records objective 3.1 part 1 of 2 audio episode
- Document your lab from the devices, not from memory short · 45 min
07 Change, configuration and lifecycle management objective 3.1 part 2 of 2 audio episode
- Find configuration drift against a golden config applied · 45 min
- Write a change request that would actually be approved short · 40 min
08 Disaster recovery, redundancy and continuity objective 3.3 part single audio episode
- Fail over a default gateway and time the outage applied · 50 min
- Domain 3 capstone — run the branch for a week capstone · 150 min
- Calculate RTO, RPO and what redundancy actually buys short · 40 min
09 Remote access and out-of-band management objective 3.5 part single audio episode
- Lock yourself out on purpose and recover out of band applied · 45 min
- Replace password SSH with keys, then lock it down short · 40 min

4. Network Security 14% of the exam

01 Security fundamentals: CIA, AAA and least privilege objective 4.1 part 1 of 3 audio episode
- Classify twelve controls into the right category short · 35 min
02 Authentication, authorization and compliance objective 4.1 part 2 of 3 audio episode
- Watch 802.1X decide whether a port may join short · 50 min
03 Physical security, segmentation and deception objective 4.1 part 3 of 3 audio episode
- Segment an IoT network that cannot be patched applied · 50 min
- Build a DMZ and prove the traffic rules hold short · 50 min
04 Attacks and their impact on the network objective 4.2 part single audio episode
- Stand up a rogue DHCP server and catch it applied · 50 min
- Watch ARP poisoning happen in a closed lab short · 45 min
05 Hardening, access control and network defences objective 4.3 part single audio episode try it
- Build a screened subnet and prove the containment applied · 55 min
- Domain 4 capstone — secure the network you built capstone · 150 min
- Order an ACL so the first match is the right one short · 45 min

5. Network Troubleshooting 24% of the exam

01 The troubleshooting methodology objective 5.1 part single audio episode
- Isolate two simultaneous faults without guessing applied · 55 min
- Walk one fault through the seven steps short · 45 min
02 Cabling and physical-layer faults objective 5.2 part 1 of 2 audio episode
- Read increasing interface counters and a duplex mismatch short · 45 min
03 Cable testing and certification tools objective 5.2 part 2 of 2 audio episode
- Diagnose PoE budget and an optic by its numbers applied · 50 min
- Tell the four port-down states apart short · 45 min
04 Troubleshooting network services objective 5.3 part single audio episode try it
- Catch a duplicate IP and a pool exhaustion applied · 55 min
- Reach some hosts and not others — the mask fault short · 45 min
05 Troubleshooting performance and throughput objective 5.4 part single audio episode
- Find the bottleneck with iperf and RTT applied · 55 min
- Measure latency, jitter and loss as separate things short · 45 min
06 Command-line diagnostic tools objective 5.5 part 1 of 2 audio episode try it
- Run the ping ladder and read what each rung means short · 45 min
07 Hardware tools and device commands objective 5.5 part 2 of 2 audio episode
- Locate a device and prove its VLAN applied · 50 min
- Domain 5 capstone — troubleshoot the network you built capstone · 150 min
- Ask the device what it believes with show commands short · 45 min

Supplementary not examined — background reading

01 Building a network lab you can break part single audio episode
- Build the two-subnet lab every later lab uses short · 60 min
02 Binary and hexadecimal for networking part single audio episode
- Do the AND operation a router does short · 30 min

The exam simulator

500 questions, every one mapped to an objective and to the lesson that teaches it. Timed full-length papers drawn to the real domain split, retakes weighted to your weak areas, and a readiness report from your own results.

Open the simulator See the paid tier

Every lesson has an audio episode, and it plays in the lesson itself — there is nothing extra to sign up for.

The episodes are also a podcast: listen on Spotify.

This is an independent study companion for CompTIA Network+ N10-009 and is not produced by or endorsed by CompTIA.