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IntermediatePublished 2026-07-03

Static Routing Troubleshooting: Return Routes & Bad Next-Hops

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Troubleshoot classic static routing and connectivity issues in a 3-router, 2-site network. Faults seeded include a missing return route, wrong next-hop/mask, and a missing/misconfigured default route. Learners must identify and correct Layer 3 faults to restore end-to-end reachability between branch clients.

Track
Est. time
45 minutes
Difficulty
Intermediate
Topics

Learning objectives

  • Diagnose typical static routing faults including missing return routes, wrong next-hop, and default route errors.
  • Utilize 'show ip route', 'ping', and 'traceroute' to verify Layer 3 reachability.
  • Restore bi-directional communication by correcting configuration errors.
  • Understand common symptoms and remediation steps for one-way reachability.

Troubleshooting focus

  • Identify a missing static route causing one-way communication.
  • Detect and fix incorrect next-hop addresses and subnet masks in static routes.
  • Spot missing or incorrect default routes limiting remote destination reachability.
  • Verify fixes using Layer 3 diagnostic commands and end-to-end pings.

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Grade your work

How this lab is graded
  • Build it your way. Where a lab lets you choose a value — a VLAN name, an interface description — grading checks that you configured it, not which name you picked. Names that another line has to reference, like an ACL applied with access-class, are stated in the guide and do have to match.
  • Addresses, modes and protocol keywords are exact. An IP address, a subnet mask, switchport mode trunk, an encapsulation — these carry the meaning of the lab, so they are graded as written in the guide.
  • Grading reads your saved configuration. Export the lab from CML after you have configured it, and make sure anything you set is in the running-config — a change that only exists in a terminal session never reaches the grader.
  • You can submit as many times as you like. Your best score stands, and each attempt tells you which checks passed so you can work the gaps.
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