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We gave away our hardest lessons.
On purpose.
Anyone can make the easy stuff sound simple. These are the six objectives students actually struggle with — subnetting, OSPF, BGP path selection, cryptography, identity management — taught completely free, with the same diagrams, labs, and mastery checks as the paid course. If these make sense, the rest of the course will too.
IPv4 Addressing and Subnetting
The single most common 'I don't get it' moment in all of networking — and the one every other CCNA topic quietly depends on.
Open the free lesson →Single-Area OSPFv2: Adjacencies, DR/BDR, and Router ID
The classic hardest CCNA protocol. If this clicks, everything else in IP Connectivity gets easier.
Open the free lesson →CCNP ENCOR
See the full course →OSPF Area Types: Stub, Totally Stubby, and NSSA
CCNP-level OSPF, well past what CCNA covers — a notorious sticking point even for experienced engineers.
Open the free lesson →BGP Neighbor Establishment and Best-Path Selection
Widely regarded as the single hardest ENCOR objective. The ordered tie-breaking list is brutal to memorize — until it isn't.
Open the free lesson →Security+
See the full course →Cryptographic Solutions: PKI, Hashing, and Digital Signatures
The densest, most intimidating objective in the whole exam — symmetric vs. asymmetric, hashing vs. encryption, PKI chains of trust.
Open the free lesson →Identity and Access Management
SAML vs. OAuth vs. OIDC, and MAC vs. DAC vs. RBAC vs. ABAC — the most commonly confused cluster of concepts in Security+.
Open the free lesson →