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INCIDENT #039 · BGP

The onboarding typo

Medium25 minutesPro lab

The incident

Los Angeles edge. A partner branch shares the aggregation router but not the service handoff. Direct uplink connectivity works, but remote routers no longer learn either service prefix from the service edge. Investigate the two service networks from R1: 10.205.224.0/24 to 10.205.230.0/24 (TCP/443), and 10.205.225.0/24 to 10.205.231.0/24 (TCP/8443).

Your objective

Restore both authorized service transports and return reachability, including clients and service hosts in both halves of the primary subnet. Keep R5 blocked from both service transports, keep SSH blocked to both service subnets, and preserve monitoring between R1 and R3. Do not change physical topology or addressing. These are network forwarding checks, not application-level transactions.

The network

Network topology5 devices 4 links

The onboarding typo — network topologyR1: Branch edge. R2: Aggregation. R3: Service handoff. R4: Service gateway. R5: Partner edge. R1 connects to R2. R2 connects to R3. R3 connects to R4. R2 connects to R5. Connections show physical links, not service health.R1 ↔ R2 · 10.205.240.0/30R2 ↔ R3 · 10.205.241.0/30R3 ↔ R4 · 10.205.242.0/30R2 ↔ R5 · 10.205.243.0/30R1Branch edgeR1 · Branch edge · Starting deviceR2AggregationR2 · AggregationR3ServicehandoffR3 · Service handoffR4ServicegatewayR4 · Service gatewayR5Partner edgeR5 · Partner edge
Physical links · Service health not shown
Link addressing (4)
  • R1 R210.205.240.0/30
  • R2 R310.205.241.0/30
  • R3 R410.205.242.0/30
  • R2 R510.205.243.0/30
5 devices · Cisco IOS syntax · Simulated network

What you’ll practice

ebgppeer as validationroute exchange

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