CompTIA Network+

The OSI model and encapsulation concepts

• The OSI Model and EncapsulationSeven layers describing how data travels from an application on your device to one on another device — and why almost every exam question asks "which layer," not "what happens."2 min read

Networking appliances, applications, and functions

• Core Networking AppliancesSwitch, router, firewall, access point — four devices whose roles beginners often blur, and every scenario question on the exam expects you to pick the right one.2 min read

Cloud concepts and connectivity options

• Cloud Computing ConceptsIaaS, PaaS, SaaS — three models that differ in how much control the customer has versus the cloud provider, where the real exam question is "who manages what," not memorizing each acronym.1 min read

Common networking ports, protocols, and services

• Common Ports and ProtocolsAbout 20 port numbers cover most exam questions on this topic — the trap isn't just memorizing them, it's remembering which are TCP and which are UDP, and why.1 min read

Transmission media and transceivers

• Transmission Media and TransceiversTwisted-pair copper, fiber optic, or wireless? Each medium forces a trade-off between cost, distance, and interference immunity — exactly what every scenario question here tests.1 min read

Network topologies, architectures, and types

• Network TopologiesHow are devices arranged physically or logically? Star vs. mesh vs. bus — each layout trades off cost against resilience in a clear, testable way.2 min read

IPv4 addressing schemes

• IPv4 Addressing and SubnettingHow the subnet mask determines the number of available hosts, and why /24, /27, and /30 aren't arbitrary numbers but a precise calculation that shows up in half this domain's questions.1 min read

IPv6 addressing schemes

• IPv6 Addressing128 bits, hexadecimal notation, and entirely new address types — IPv6 isn't just "longer IPv4," it's a different addressing scheme that even replaces the concept of broadcast.1 min read

Characteristics of routing technologies

• Routing TechnologiesHow does a router decide which path to pick among several possible routes to the same destination? Administrative distance first, then internal metric — in an order that never flips.1 min read

Switching technologies and features

• Switching TechnologiesHow does a switch learn where to send each frame without being told? A MAC address table built dynamically from the traffic itself — the foundation of every question about switch behavior.2 min read

Common Ethernet switching features

• VLANs and TrunkingHow does a network admin split one physical switch into several separate logical networks? A VLAN does this without any extra cabling — and the usual trap is forgetting that tagging is what makes it possible over a shared link.1 min read

Wireless standards and technologies

• Wireless Standards and TechnologiesFrom 802.11g to Wi-Fi 6 — each new wireless standard raises speed and improves efficiency, but the real difference the exam usually tests is picking the right frequency band, not the standard's name.1 min read

Organizational processes and procedures

• Organizational Processes and ProceduresWhy does a network admin refuse to patch a core router immediately even when they know the fix? Because documentation and a rollback plan are part of the fix itself, not a bureaucratic obstacle in front of it.1 min read

Network monitoring technologies

• Network Monitoring TechnologiesSNMP either asks devices itself or waits for them to speak up — a simple difference between polling and notification that actually determines how fast a fault gets noticed.1 min read

Disaster recovery concepts

• Disaster Recovery ConceptsRTO asks "how much downtime can we tolerate?" and RPO asks "how much data can we tolerate losing?" — two completely different questions that determine what kind of recovery site an organization needs.1 min read

High availability concepts

• High Availability ConceptsFive nines (99.999%) means under six minutes of downtime per entire year — a number that sounds simple but forces the network to never depend on a single component for any critical function.1 min read

Network load balancing

• Network Load BalancingA load balancer doesn't distribute requests randomly — it follows a specific algorithm and automatically removes any server that fails its periodic health check, with no manual intervention.1 min read

Security concepts

• Network Security ConceptsConfidentiality, integrity, and availability — three goals that sometimes pull in different directions, and good security balances them instead of maximizing one at the others' expense.1 min read

Types of attacks and their impact on the network

• Types of Attacks and Their Network ImpactA DDoS attack isn't stopped by a stronger firewall — the problem is that malicious traffic comes from thousands of distributed sources, not one source that can simply be blocked.1 min read

Network hardening techniques

• Network Hardening TechniquesEvery needlessly open port and running service is extra attack surface — hardening starts with reducing that surface before thinking about any additional defense.1 min read

Physical security devices

• Physical Security DevicesPhysical security isn't a substitute for digital security but an additional defense-in-depth layer — a camera doesn't physically prevent intrusion, but it raises the perceived chance of detection, discouraging many attempts before they start.1 min read

The troubleshooting methodology

• The Troubleshooting MethodologyThe first step in any fault isn't guessing the cause, it's actually identifying the problem — jumping to a fix before precisely identifying the problem is the single biggest reason repairs take longer.1 min read

Common cabling and physical interface issues

• Common Cabling and Physical Interface IssuesA cable tester reveals in seconds what guessing might take hours — an open circuit, a short, or wrong wire order are all purely physical symptoms with a direct test.1 min read

Common network service issues

• Common Network Service IssuesAn APIPA address specifically means DHCP failure, while name resolution failure with an actual network connection specifically means a DNS problem — each symptom has a completely different signature from the other.1 min read

Common performance issues

• Common Performance IssuesHigh bandwidth doesn't fix timing jitter — a wide pipe doesn't mean every drop of water arrives at the same steady rhythm.1 min read

Common wireless connectivity issues

• Common Wireless Connectivity IssuesA strong signal doesn't necessarily mean a good connection — interference from a neighboring network on the same channel slows actual throughput even while the signal indicator shows full bars.1 min read