Data center: New client addresses cannot use the service
The incident
Application workers connect to database and connection-pool subnets through separate access and service aggregation layers. Each of three routed leaves connects to both spines. Partner monitoring and service gateways sit behind different leaves. A client at .10 can use the primary service, but a client at .200 in the same subnet cannot. Both clients can reach the monitoring destination. Investigate database connectivity from R1: 10.168.0.0/24 to 10.168.10.0/24 (TCP/5432), and 10.168.1.0/24 to 10.168.11.0/24 (TCP/6432).
Your objective
Restore both authorized service transports and return reachability, including clients and service hosts in both halves of the primary subnet. Keep R4 blocked from both service transports, keep SSH blocked to both service subnets, and preserve monitoring between R1 and R7. Do not change physical topology or addressing. These are network forwarding checks, not application-level transactions.
The network
Link addressing (8)
- R1 R2
10.168.16.0/30 - R1 R3
10.168.17.0/30 - R4 R2
10.168.18.0/30 - R4 R3
10.168.19.0/30 - R5 R2
10.168.20.0/30 - R5 R3
10.168.21.0/30 - R5 R6
10.168.22.0/30 - R4 R7
10.168.23.0/30
What you’ll practice
Interview exercises are inspired by common industry competencies. They are not proprietary interview questions.