Subnet Mask
Learn what "local vs remote" means and why the subnet mask affects routing and connectivity.
DHCP
Understand how devices automatically receive IP addresses, gateways, and DNS settings.
DNS
See how domain names translate to IP addresses and why DNS causes "internet feels broken" issues.
Default Gateway
Learn how the default gateway lets devices reach the internet and what happens when it's missing or wrong.
NAT (Network Address Translation)
Understand how routers translate private IPs to a single public IP and how PAT works on home networks.
OSI Model (All 7 Layers)
Learn all 7 OSI layers with memory tricks and troubleshooting examples — a guaranteed A+ exam topic.
TCP vs UDP Explained
Understand reliability vs speed, when each protocol is used, and how they appear on the exam.
APIPA (169.254.x.x)
Learn why 169.254 appears and what it tells you about DHCP and connectivity problems.
Network Troubleshooting Commands
ipconfig, ping, tracert, nslookup, netstat — the commands every IT tech uses daily with a step-by-step diagnostic workflow.
Common Port Numbers
Quick reference for high-yield ports like 80, 443, 53, 22, and 3389 with memory tips.
What Is a MAC Address?
Layer 2 hardware addressing, OUI vs device ID, how switches use MAC tables, and ARP explained.
IPv4 vs IPv6 Explained
Why IPv6 exists, how address formats differ, and the special addresses — loopback, APIPA, link-local — the exam tests on both.
Router vs Switch
Layer 3 vs Layer 2, IP vs MAC, WAN vs LAN — how each device works and when you need both in a real network.
Firewall Basics
Allow/deny rules, implicit deny, stateful vs stateless, host vs network firewalls, and Windows Defender profiles.
Speed Up Your Exam Prep
If you're studying consistently, practice tests + a structured guide will get you to passing faster.
Common A+ Networking Scenarios
ipconfig /renewipconfig /flushdns443 is open / not blocked by firewall rulesipconfig for blank gateway → fix DHCP or static configReading about networking is one thing.
Doing it is how it actually sticks.
The fastest way to make concepts like subnetting, DHCP, and switching click is to run them on real hardware — or at minimum, a home lab VM. Once you've pinged a gateway you set up yourself, you won't forget what a default gateway does.
I put together a guide to building your first lab on a tight budget, plus a list of the exact gear worth buying when you're ready to go physical.
Ready to Start Studying?
Compare the best CompTIA A+ resources and free practice exams.