Networking courses

An interactive networking course – explained visually, step by step, jargon-free. Try it live in the simulator.

How networks work — Understand networks from the ground up: why they exist, how devices talk, and how your message reaches exactly where it…
ISO/OSI and TCP/IP: the network map — Name every layer and device. Walk the network layer by layer (L1–L7), add the TCP/IP model, cross-layer firewalling…
DNS and names in the network — From the “phone book” into depth: who asks whom (client, resolver, authority), cache and TTL, your own local DNS in a…
Switching and VLANs — Switching in practice: split the network into VLANs, set up access and trunk ports, route between VLANs at L3 and…
Routing and IP addresses — How a router picks a path: the routing table and longest-prefix, default and static routes, NAT/PAT — and then further…
Network security — Firewalls in practice: inside/outside/DMZ zones, rules, stateful inspection, VPN and common misconfigurations.
Build your first company network — A consolidation course: turn a small company’s requirements into a working, secure network. You put courses 1–5 to work…
Redundancy and Spanning Tree — Why one link isn’t enough: loops and broadcast storms, Spanning Tree (root bridge, port states), RSTP, EtherChannel.
OSPF in depth — Dynamic routing: why static isn’t enough, how OSPF routers find each other (Hello, DR/BDR), the shared map (LSDB)…
Advanced security (DPI, IDS/IPS) — Defense in depth: what a firewall can’t see, stateful inspection, DPI and TLS, IDS vs IPS, real attacks (port scan…
The switch in depth — L2 mechanics and security: MAC table and flooding, the 802.1Q frame, port security, VLAN hopping, DHCP snooping and…
The router in depth — L3 mechanics and security: the routing table and administrative distance, packet processing, NAT/PAT types, default and…
Wireless in practice — Wi-Fi from the ground up: joining, bands and channels, Wi-Fi generations, coverage and roaming, mesh vs repeater…
Wi-Fi: security in depth — Wireless security without the gloss: how WPA2’s handshake and WPA3 (SAE) really work, PMF, enterprise 802.1X/EAP…
OT/ICS: industrial network security — Networks that move real things: PLCs, HMIs and the historian, availability first, the Purdue model and IT/OT…
Network resilience and scaling — Networks that survive a fault and bear a surge: the single point of failure (SPOF) and high availability (N-1), the HA…
When the network breaks: troubleshooting — Method instead of guessing: turning a complaint into a fault description, scope, bottom-up and top-down approaches and…
Zero Trust and microsegmentation — Why a wall at the network border is not enough and what to do instead: the attacker pivot and lateral movement, the…
Monitoring, logging and detection — How you find out what is really happening in your network: why nothing can be traced without logs, the log server as…
Networking to the cloud — What the cloud looks like through the eyes of the network: the cloud as someone else’s datacenter behind the network…
When it happens: incident response — What to do when something happens in the network that should not have: the response phases and preparation (log server…
Encryption in the network: what it hides and what not — From the Caesar cipher and frequency analysis to today: what is visible on the cable and what encryption really hides…