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CCNP ENARSI lab 12 of 35

Troubleshooting redistribution, administrative distance and route control

Six months after the OSPF and EIGRP domains were joined, redundancy has quietly disappeared and parts of the plant are unreachable. Find six faults in seed metrics, prefix lists, route maps and administrative distance, and restore the design.

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It needs Lite: its 4 nodes are set to 4 vCPU and 2,048 MB in total. That fits the free demo too.

In your workspace: Shared, then CCNP ENARSI 300-410 guided labs, then 12 - Troubleshooting redistribution administrative distance and route control

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Level
Advanced
Time
About 80 minutes
Nodes need
4 vCPU, 2,048 MB
Smallest plan
Lite

The scenario

This is Ravensworth Foods again (lab 11), six months later. The design hasn't changed: R2 and R3 redistribute in both directions with tags 90 (EIGRP → OSPF) and 110 (OSPF → EIGRP), each boundary router only sends plant prefixes (prefix list PLANT: 172.16.0.0/16 and all its subnets, and 192.168.44.0/24) into OSPF, seed metric 100000 100 255 1 1500 into EIGRP, and **distance ospf external 175 on both boundary routers. R4 redistributes only its control network (Loopback44) into EIGRP. HQ must reach the plant through both** boundary routers, and the plant must reach HQ through both.

After a quarter of "small changes" the monitoring team reports:

  1. "R4 only has one path back to HQ (through R3); the R2 path disappeared."
  2. "HQ can't reach the plant LAN 172.16.4.0/24 at all."
  3. "HQ can't reach the plant control network 192.168.44.0/24, and an unknown network 192.168.4.0/24 has appeared in the plant."
  4. "HQ monitoring can't reach R3's management address 10.255.0.3 although R3 is up."
  5. "R3 sends plant traffic the long way round, through HQ." (visible once tickets 2 and 3 are fixed)
DeviceInterfaceAddressDomain
R1Gi0/0 / Gi0/1 / Lo110.0.12.1 / 10.0.13.1 / 10.1.1.1 /24OSPF
R2Gi0/0 / Gi0/110.0.12.2/24 (OSPF) / 172.16.24.2/24 (EIGRP)both
R3Gi0/0 / Gi0/110.0.13.3/24 (OSPF) / 172.16.34.3/24 (EIGRP)both
R4Gi0/0 / Gi0/1172.16.24.4 / 172.16.34.4 /24EIGRP
R4Lo1 / Lo4 / Lo44172.16.4.1 / 192.168.4.1 / 192.168.44.1 /24plant LAN / spare (never advertise) / control
R1–R3Lo010.255.0.n/32OSPF

What you’ll practise

  • Trace a prefix through redistribution: origin, redistribution point, other domain
  • Diagnose missing seed metrics, missing route maps and prefix-list length errors
  • Diagnose a route map that matches the wrong object
  • Recognise administrative-distance faults, including a distance of 255

The tasks

  1. Follow each missing prefix from its source
  2. Restore redistribution into OSPF (tickets 2 and 3)
  3. Restore redistribution into EIGRP (ticket 1)
  4. Fix the administrative-distance faults (tickets 4 and 5)
  5. Prove the design is restored

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 redistribution administrative distance and route control4 nodes, 4 links. Every link is listed as text below the diagram.R1R2R3R4Gi0/0Gi0/0Gi0/1Gi0/0Gi0/1Gi0/0Gi0/1Gi0/1
4 nodes, with the interface names each link uses. On a narrow screen, scroll the diagram sideways.
Every link, as text
  • R1 Gi0/0 to R2 Gi0/0
  • R1 Gi0/1 to R3 Gi0/0
  • R2 Gi0/1 to R4 Gi0/0
  • R3 Gi0/1 to R4 Gi0/1
Nodes in Troubleshooting redistribution, administrative distance and route control, with the image each runs and the vCPU and RAM it’s set to
NodeDeviceImage in Add NodeSet to
R1Cisco IOSvvios-adventerprisek9-m.spa.159-3.m91 vCPU, 512 MB
R2Cisco IOSvvios-adventerprisek9-m.spa.159-3.m91 vCPU, 512 MB
R3Cisco IOSvvios-adventerprisek9-m.spa.159-3.m91 vCPU, 512 MB
R4Cisco IOSvvios-adventerprisek9-m.spa.159-3.m91 vCPU, 512 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 CCNP ENARSI 300-410 guided labs.

  3. Open 12 - Troubleshooting redistribution administrative distance and route control 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.

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