Start learning

VLAN Playground

Move hosts between VLANs and test whether traffic gets through. Shows broadcast domains, inter-VLAN routing and guest isolation.

Build labRuns in your browser · nothing is saved or sent

labs.vlan one switch, three VLANs

A VLAN is a broadcast domain, not a firewall

Putting hosts in different VLANs splits one switch into separate broadcast domains, and that is the whole trick: a broadcast in VLAN 10 is never seen in VLAN 20. It also means traffic cannot cross between them on its own: something has to route it. Turn the router on in this lab and the same two hosts start talking; leave the guest VLAN walled off and they still do not, because separation and routing are two different decisions.

Learn the idea behind the lab

This lab is the practice; VLANs & trunking explains tagging and trunk links.

Keep going

All labs
Cable termination RJ-45 Wiring Game Drag the eight strands into the right pin order for T568A or T568B, then check your work. Straight-through and crossover, with the answer on request. Build lab Start lab Addressing Subnet Designer Size a block for every department from one base network. The lab checks capacity and alignment, then shows how much space your design wasted. Build lab Start lab Security Firewall Simulator Build an ordered rule-set and send a packet through it. Watch the top-down scan stop at the first match, then reorder and watch the verdict flip. Build lab Start lab