Network challenges
Can you fix the network?
Each challenge hands you a small network that is already built and already broken, plus one goal. Find the fault with real show and ping commands, fix it, and the grader checks the live network — not your typing. Beat the par time and command count for three stars, then send the link to a friend: they get their own fresh copy.
01The desk that can't leave its LAN
PC1 pings the desk next to it but never reaches the server. Find the missing setting and get it online.
starter5 devicespar 2:30Default gateway · IP addressingPlay
02The staff PC on the guest VLAN
A staff desk was plugged into the wrong switch port config and lost the file server. Put it back without letting the guest in.
starter5 devicespar 3:00VLANs · Access portsPlay
03The VLAN that stops at the trunk
Two switches, one trunk, and a server nobody on the other switch can reach. Find what the trunk refuses to carry.
core5 devicespar 4:00Trunking · 802.1QPlay
04The OSPF neighbours that never meet
Two routers run OSPF over a working link, yet neither learns a single route. Get the adjacency to FULL.
core4 devicespar 5:00OSPF · Dynamic routingPlay
05The ACL that blocks the wrong person
An access list meant to keep a guest laptop off the server locked out a staff PC instead. Make the filter match the policy.
core5 devicespar 5:00ACLs · Traffic filteringPlay
Want to be walked through a fault instead? The guided builds include step-by-step troubleshooting labs.