THE LINEMAN
INTERACTIVE STUDY TOOLS · FORTINET HOME LAB
STUDYING IN PUBLIC.
ONE PACKET AT A TIME._
★ CCNA PRACTICE LABS
64 SwitchLab lessons, from your first switch port to a complete campus. Pick a guided lab, troubleshoot a fault, or try a capstone.
Existing Packet Tracer and browser labs are still available. Follow the study path to track your progress.
Brand new? How to study for the CCNA · Want it ordered & tracked? The guided study path ▶
★ LATEST POSTS
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.
> VLSM CALC...
> /25 = 128 hosts
> /26 = 64 hosts
> /27 = 32 hosts
> DONE_
(WITH ANSWERS EXPLAINED) Twelve worked problems — network & broadcast, host counts, masks, VLSM sizing, wildcards, the magic-number method — each with a click-to-reveal answer. Try it, then check yourself. Q&A [ CCNA · OSPF · DR/BDR ] HOW IS THE OSPF DR/BDR
ELECTED? Priority first, then Router ID — why the newest router almost never wins, how to force the DR with ip ospf priority, and why point-to-point links skip the election entirely. 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. BLOG [ CCNA · CAREER ] IS THE CCNA WORTH IT IN 2026?
AN HONEST TAKE A working network analyst's honest answer — the real case for it, the honest case against, who shouldn't bother, what it costs in time and money, and a clear way to decide. 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.
★ ABOUT
░ DD ░
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I used to hold the line on a football field. Now I hold it in a network rack.
I'm Dylan Doyle — a network analyst at Halton District School Board, based in Burlington, ON. I studied the BIT NET joint program between Carleton University and Algonquin College — four years learning how networks actually work, then two summers at Halton's IS-IS department proving it. They kept me on full time after graduation.
Now I'm CCNA 200-301 certified and working toward the CCNP Enterprise, running a Fortinet home lab — FortiGate 60F, FortiSwitch 124D, and a FortiAP 421E — and self-hosting everything I build on Linux from scratch. This site included.
Outside the rack, I'm training. I've completed an Olympic triathlon and a half marathon, and I'm building toward a full Ironman — slowly, deliberately, the same way I approach everything. One packet at a time.
TheLineman is where I document all of it — the certs, the lab, the grind. If you're on a similar path, pull up a chair._