Service edge: A healthy control plane hides a dropped host
The incident
Internal API clients and an independent observability edge share a transit network with an isolated partner segment. Independent north and south core paths connect the ingress and egress routers. OSPF neighbors and the service /24 route look healthy, but one host at .10 is unreachable. Another host in the same subnet responds. Investigate internal API transport from R1: 10.172.32.0/24 to 10.172.42.0/24 (TCP/8443), and 10.172.33.0/24 to 10.172.43.0/24 (TCP/443).
Your objective
Restore both authorized service transports and return reachability, including clients and service hosts in both halves of the primary subnet. Keep R3 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
Link addressing (6)
- R1 R2
10.172.48.0/30 - R2 R3
10.172.49.0/30 - R2 R4
10.172.50.0/30 - R3 R5
10.172.51.0/30 - R4 R5
10.172.52.0/30 - R5 R6
10.172.53.0/30
What you’ll practice
Interview exercises are inspired by common industry competencies. They are not proprietary interview questions.