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CCNP ENARSI lab 33 of 35

Troubleshooting infrastructure security and services

A hardening project went wrong: OSPF is down, TACACS+ logins fail, the NMS can't poll or receive anything, PCs get no addresses and IPv6 to the core is dead. Seven faults in AAA, ACLs, an IPv6 filter, CoPP, SNMP, syslog and DHCP relay, each found from the evidence a real engineer would use.

Run this lab

It needs Lite: its 4 nodes are set to 4 vCPU and 3,072 MB in total. That fits the free demo too.

In your workspace: Shared, then CCNP ENARSI 300-410 guided labs, then 33 - Troubleshooting infrastructure security and services

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Level
Advanced
Time
About 80 minutes
Nodes need
4 vCPU, 3,072 MB
Smallest plan
Lite

The scenario

Kite Logistics hired a contractor to "harden" its branch router R1 before an audit. The contractor left on Friday. On Monday:

  1. "R1 lost its OSPF neighbour R2; the branch can't reach head office."
  2. "Our TACACS+ accounts don't work on R1 any more; only the local fallback account does."
  3. "The NMS can't poll R1 with SNMPv3 and receives no traps or syslog from it."
  4. "PCs on the staff LAN get no IP address."
  5. "IPv6 between R1 and R2 is dead, but IPv6 pings were explicitly allowed."

The design: OSPF area 0 between R1 and R2; R1's VTY lines use TACACS+ (server SRV 10.35.100.100, key **Tac-Key-2026**) with local fallback; SNMPv3 user nms (authPriv) may poll from SRV only, and R1 sends SNMPv3 traps to SRV; R1 sends syslog at informational to SRV; the staff LAN gets DHCP from R2 (10.35.12.2) through R1's relay; R1's inbound filters on Gi0/0 allow the core's traffic, including routing and IPv6 neighbour discovery; CoPP protects R1 but must never block management from the management LAN.

DeviceInterfaceAddressNotes
R1Gi0/010.35.12.1/24, 2001:db8:35:12::1/64to R2
R1Gi0/110.35.100.1/24management LAN (SRV)
R1Gi0/210.35.10.1/24staff LAN (PC1)
R2Gi0/010.35.12.2/24, 2001:db8:35:12::2/64core router, DHCP server
SRVeth010.35.100.100/24TACACS+, syslog, SNMP traps, snmpget

TACACS+ users: alice / Alice-Pass1 (privilege 15). Local fallback: localadmin / Local-Pass1. SNMPv3: nms, SHA Auth-Pass-26, AES-128 Priv-Pass-26.

What you’ll practise

  • Troubleshoot AAA server communication and fallback
  • Find ACL entries that block routing protocols and IPv6 neighbour discovery
  • Read CoPP class order and counters to find dropped management traffic
  • Troubleshoot SNMPv3 traps and syslog severity levels
  • Troubleshoot a DHCP relay

The tasks

  1. OSPF is down (ticket 1)
  2. IPv6 is dead (ticket 5)
  3. TACACS+ logins fail (ticket 2)
  4. The NMS sees nothing (ticket 3)
  5. No DHCP addresses (ticket 4)

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 infrastructure security and services4 nodes, 3 links. Every link is listed as text below the diagram.R1R2PC1SRVGi0/0Gi0/0Gi0/1eth0Gi0/2eth0
4 nodes, with the interface names each link uses. On a narrow screen, scroll the diagram sideways.
Every link, as text
  • R2 Gi0/0 to R1 Gi0/0
  • R1 Gi0/1 to SRV eth0
  • R1 Gi0/2 to PC1 eth0
Nodes in Troubleshooting infrastructure security and services, 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
PC1VPCS hostBuilt in to EVE-NGCounted as 1 vCPU, 1,024 MB
SRVEVE-NG GUI server (Docker)eve-gui-server:latest1 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 CCNP ENARSI 300-410 guided labs.

  3. Open 33 - Troubleshooting infrastructure security and services 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.