CCNA STUDY GUIDES_
Plain-English CCNA articles. No build-in-public stories, no personal essays — just the concepts, troubleshooting, and reference material you'd actually read while studying. Looking for chronological everything? See ARTICLES. Looking for free Packet Tracer lab files? See LABS. Brand new? Start with how to study for the CCNA.
★ NEED IT MAPPED TO THE EXAM BLUEPRINT? GO TO THE STUDY HUB ★ Every guide on this list cross-referenced against all 53 CCNA 200-301 exam topics ▶
GUIDE
[ CCNA · TRANSPORT · TCP/UDP ]
TCP vs UDP:
THE TRANSPORT LAYER, MADE CONCRETE The 3-way handshake, ports and sockets, reliability vs speed, and the well-known port for every CCNA service — then watch it move in the live packet visualizer. START HERE [ CCNA · GETTING STARTED ] HOW TO STUDY
FOR THE CCNA New to the CCNA? Start here — what the 200-301 exam is, what it costs, how long it takes, the six exam domains, and a free read-drill-lab plan you can start today. PATH [ CCNA · GUIDED STUDY PATH ] THE CCNA
STUDY PATH The exam topics in the order to learn them — each bundling the article, lab, and drill — with progress tracking so you can see how far you've come. The journey companion to the Study Hub's map. GUIDE [ CCNA · OSPF · LSA TYPES ] OSPF MULTI-AREA & LSA TYPES:
WHAT EACH LSA CARRIES Why OSPF carves the domain into areas, the four router roles (internal / backbone / ABR / ASBR), every CCNA-relevant LSA type (1, 2, 3, 4, 5, 7) with originator and flooding scope, and the five OSPF packet types tied to the adjacency state machine. GUIDE [ CCNA · IPV6 ] IPV6 FOR THE CCNA:
COMPRESSION, TYPES & EUI-64 The short IPv6 guide for the exam — 128-bit anatomy, the two compression rules, the six address types, and EUI-64 step-by-step. Paired with three free drill tools. GUIDE [ CCNA · ROUTING · OSPF ] OSPF EXPLAINED:
LINK-STATE ROUTING FOR THE CCNA No CLI — just the mental model. Distance-vector vs link-state, LSDB & SPF, areas, router-ID picking order, the process-ID trap, and wildcard masks. Read this before you touch the lab. GUIDE [ CCNA · OSPF · TROUBLESHOOTING ] OSPF ADJACENCY STATES:
WHY YOURS IS STUCK IN EXSTART Every OSPF state — DOWN, INIT, 2-WAY, EXSTART, EXCHANGE, FULL — and the one-line fix for each failure mode. MTU mismatch, one-way Hellos, flapping timers, and the troubleshooting decision tree. GUIDE [ NETWORKING · VPN · TROUBLESHOOTING ] THE 1500-BYTE LIE:
WHY YOUR VPN HANGS ON BIG FILES The VPN's up. Pings are 18ms. Web works. Then a 50MB download hangs at 4%. Here's the math, the captures, and the MSS-clamping fix — per platform. REFERENCE [ CCNA · REFERENCE ] SUBNETTING CHEAT SHEET:
CIDR, BLOCK SIZES & HOST COUNTS Every prefix /8 through /32 in one place. Subnet mask, block size, total addresses, usable hosts, and wildcard mask. Save the image or bookmark the page. GUIDE [ CCNA · SUBNETTING ] WHY SUBNETTING FINALLY
CLICKED FOR ME Three weeks of confusion. One diagram that changed everything. Here's the mental model that actually works — and why most guides start from the wrong end.
THE TRANSPORT LAYER, MADE CONCRETE The 3-way handshake, ports and sockets, reliability vs speed, and the well-known port for every CCNA service — then watch it move in the live packet visualizer. START HERE [ CCNA · GETTING STARTED ] HOW TO STUDY
FOR THE CCNA New to the CCNA? Start here — what the 200-301 exam is, what it costs, how long it takes, the six exam domains, and a free read-drill-lab plan you can start today. PATH [ CCNA · GUIDED STUDY PATH ] THE CCNA
STUDY PATH The exam topics in the order to learn them — each bundling the article, lab, and drill — with progress tracking so you can see how far you've come. The journey companion to the Study Hub's map. GUIDE [ CCNA · OSPF · LSA TYPES ] OSPF MULTI-AREA & LSA TYPES:
WHAT EACH LSA CARRIES Why OSPF carves the domain into areas, the four router roles (internal / backbone / ABR / ASBR), every CCNA-relevant LSA type (1, 2, 3, 4, 5, 7) with originator and flooding scope, and the five OSPF packet types tied to the adjacency state machine. GUIDE [ CCNA · IPV6 ] IPV6 FOR THE CCNA:
COMPRESSION, TYPES & EUI-64 The short IPv6 guide for the exam — 128-bit anatomy, the two compression rules, the six address types, and EUI-64 step-by-step. Paired with three free drill tools. GUIDE [ CCNA · ROUTING · OSPF ] OSPF EXPLAINED:
LINK-STATE ROUTING FOR THE CCNA No CLI — just the mental model. Distance-vector vs link-state, LSDB & SPF, areas, router-ID picking order, the process-ID trap, and wildcard masks. Read this before you touch the lab. GUIDE [ CCNA · OSPF · TROUBLESHOOTING ] OSPF ADJACENCY STATES:
WHY YOURS IS STUCK IN EXSTART Every OSPF state — DOWN, INIT, 2-WAY, EXSTART, EXCHANGE, FULL — and the one-line fix for each failure mode. MTU mismatch, one-way Hellos, flapping timers, and the troubleshooting decision tree. GUIDE [ NETWORKING · VPN · TROUBLESHOOTING ] THE 1500-BYTE LIE:
WHY YOUR VPN HANGS ON BIG FILES The VPN's up. Pings are 18ms. Web works. Then a 50MB download hangs at 4%. Here's the math, the captures, and the MSS-clamping fix — per platform. REFERENCE [ CCNA · REFERENCE ] SUBNETTING CHEAT SHEET:
CIDR, BLOCK SIZES & HOST COUNTS Every prefix /8 through /32 in one place. Subnet mask, block size, total addresses, usable hosts, and wildcard mask. Save the image or bookmark the page. GUIDE [ CCNA · SUBNETTING ] WHY SUBNETTING FINALLY
CLICKED FOR ME Three weeks of confusion. One diagram that changed everything. Here's the mental model that actually works — and why most guides start from the wrong end.