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INCIDENT #226 · ROUTING

Remote access: Both services fail after route cleanup

Hard30 minutesPro lab

The incident

Managed remote clients reach access-service gateways over an enterprise transit chain; unmanaged devices use a separate branch. The service path crosses four transport stages, so local link health does not locate an end-to-end failure. Both service subnets stopped responding after a route cleanup. Monitoring traffic still succeeds and the client route table is not empty. Investigate access gateway transport from R1: 10.179.32.0/24 to 10.179.42.0/24 (TCP/443), and 10.179.33.0/24 to 10.179.43.0/24 (UDP/1194).

Your objective

Restore both authorized service transports and return reachability, including clients and service hosts in both halves of the primary subnet. Keep R2 blocked from both service transports, keep SSH blocked to both service subnets, and preserve monitoring between R1 and R4. Do not change physical topology or addressing. These are network forwarding checks, not application-level transactions.

The network

Network topology6 devices 5 links

Remote access: Both services fail after route cleanup — network topologyR1: Branch edge. R2: Access handoff. R3: West transit. R4: East transit. R5: Service handoff. R6: Service gateway. R1 connects to R2. R2 connects to R3. R3 connects to R4. R4 connects to R5. R5 connects to R6. Connections show physical links, not service health.R1 ↔ R2 · 10.179.48.0/30R2 ↔ R3 · 10.179.49.0/30R3 ↔ R4 · 10.179.50.0/30R4 ↔ R5 · 10.179.51.0/30R5 ↔ R6 · 10.179.52.0/30R1Branch edgeR1 · Branch edge · Starting deviceR2Access handoffR2 · Access handoffR3West transitR3 · West transitR4East transitR4 · East transitR5ServicehandoffR5 · Service handoffR6ServicegatewayR6 · Service gateway
Physical links · Service health not shown
6 devices · Cisco IOS syntax · Simulated network

What you’ll practice

summary routeslongest prefix matchsafe remediation

Interview exercises are inspired by common industry competencies. They are not proprietary interview questions.