Everything's down: restore the network
A multi-site network is broken by three independent faults across L2, L3, and a filter. Restore end-to-end connectivity and document what you found.
Scenario
After a "small change", the whole multi-site network is down. There are three independent faults, spanning layers:
- an L2 trunking issue starving a VLAN,
- an L3/OSPF issue breaking the routed path,
- an ACL silently dropping legitimate return traffic.
Your job
Work the problem methodically, restore full Site A ↔ Site B reachability, and write a short note of what each fault was and how you fixed it.
What "done" looks like
End-to-end connectivity between a host at Site A and a host at Site B is restored, plus a clear fault/fix write-up.
Teaches: structured, layered troubleshooting and communicating findings, the thing that actually distinguishes a hireable engineer. This capstone reuses the concepts from vlan-routing-01, ospf-areas-01, and acl-policy-01.
Tooling
Arista cEOS for the switching/ACL layers and FRR (or cEOS) for OSPF. Validate on first deploy.
What gets checked
Your solution is verified against each of these:
- The access trunk carries the required VLANs again
- OSPF adjacencies are FULL and routes are present end to end
- The ACL no longer blocks legitimate return traffic
- A host at Site A can reach a host at Site B
- A short note lists each fault found and the fix applied
Solve it in your browser
No setup, no install. Write your solution in the editor and hit Check. The in-house engine renders and grades it instantly, then issues your proof the moment every check passes.
Solve in browser →Prefer your own lab?
- Build the fix locally. New to the tooling? See setting up your lab.
- Push your topology file, device configs, and any playbooks to a public repo (GitHub or GitLab).
- Submit the repo link. We review it by hand, confirm it works, and issue your proof page.