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…
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 packet finds its way across networks: the routing table, default route, static routes and NAT.
Network security — Firewalls in practice: inside/outside/DMZ zones, rules, stateful inspection, VPN and common misconfigurations.
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…