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MikroTik MTCRE lab 13 of 14

Troubleshooting a routed network

A five-router OSPF network after a weekend of changes: the branch PC can't reach the Internet. Walk the path neighbour by neighbour with RouterOS 7's OSPF tools and find five faults: an area mismatch, mismatched timers, a passive transit link, a missing default route and a typo that hides a LAN.

Run this lab

It needs Lite: its 6 nodes are set to 6 vCPU and 2,304 MB in total. That fits the free demo too.

In your workspace: Shared, then MikroTik MTCRE RouterOS v7 guided labs, then 13 - Troubleshooting a routed network

Try it free for 30 minutesRun it on Lite from £3 a day

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Level
Advanced
Time
About 60 minutes
Nodes need
6 vCPU, 2,304 MB
Smallest plan
Lite

The scenario

The weekend change window at Fernvale went badly. On Monday the branch reports that PC1 can't reach anything beyond its own router. The design is simple: five routers in a line, all in OSPF area 0, router IDs from loopbacks, and R5, the Internet edge, advertising a default route. The test host 198.51.100.10 lives on R5 and is deliberately not in OSPF: everyone reaches it through the default route.

LinkAddresses
R1–R2 · R2–R3 · R3–R4 · R4–R510.0.12.0/30 · 10.0.23.0/30 · 10.0.34.0/30 · 10.0.45.0/30 (lower router .1)
Branch LAN on R1192.168.1.0/24 (PC1 .10)

What you’ll practise

  • Troubleshoot OSPF adjacencies hop by hop with the neighbour, interface and log output
  • Recognise area ID, hello/dead timer and passive-interface faults
  • Check that the right networks are advertised and that a default route is originated
  • Prove the result end to end, both directions

The tasks

  1. R1 and R2
  2. R2 and R3
  3. R3 and R4
  4. R4 and R5
  5. Still no Internet

The Lab Tasks pane has the scenario, these tasks, the checks to run, hints and the full solution.

Topology and devices

The network as it opens in EVE-NG, drawn from the lab’s own canvas, and the image each node runs.

Topology of Troubleshooting a routed network6 nodes, 5 links. Every link is listed as text below the diagram.R1R2R3R4R5PC1ether1ether1ether2ether1ether2ether1ether2ether1ether2eth0
6 nodes, with the interface names each link uses. On a narrow screen, scroll the diagram sideways.
Every link, as text
  • R1 ether1 to R2 ether1
  • R2 ether2 to R3 ether1
  • R3 ether2 to R4 ether1
  • R4 ether2 to R5 ether1
  • R1 ether2 to PC1 eth0
Nodes in Troubleshooting a routed network, with the image each runs and the vCPU and RAM it’s set to
NodeDeviceImage in Add NodeSet to
R1MikroTik RouterOSmikrotik-7.14.21 vCPU, 256 MB
R2MikroTik RouterOSmikrotik-7.14.21 vCPU, 256 MB
R3MikroTik RouterOSmikrotik-7.14.21 vCPU, 256 MB
R4MikroTik RouterOSmikrotik-7.14.21 vCPU, 256 MB
R5MikroTik RouterOSmikrotik-7.14.21 vCPU, 256 MB
PC1VPCS hostBuilt in to EVE-NGCounted as 1 vCPU, 1,024 MB

How to open this lab

  1. Sign in to your workspace at lab.cloudlabbox.com.

  2. In File Manager, open Shared, then the folder MikroTik MTCRE RouterOS v7 guided labs.

  3. Open 13 - Troubleshooting a routed network and start its nodes, then open Lab Tasks for the scenario and the steps.

The lab is read-only. You can start the nodes and configure the devices, but changes to the topology can’t be saved. To change it, rebuild it in your own folder.

More MikroTik MTCRE labs

All MikroTik MTCRE labs

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CloudLabBox is independent of MikroTik. The lab follows exam topics and isn’t vendor training material; vendor names identify the exams and the images in the workspace.