Backup network: The service edge loses its neighbor
The incident
Backup agents traverse a routed storage boundary while replication monitoring and a lab tenant share a separate branch. Client and service access branches each have their own transit router on either side of the regional hub. The directly connected service-edge link responds, but the OSPF adjacency across it is absent. Other adjacencies and monitoring traffic remain healthy. Investigate backup transport from R1: 10.174.96.0/24 to 10.174.104.0/24 (TCP/2049), and 10.174.97.0/24 to 10.174.105.0/24 (UDP/111).
Your objective
Restore both authorized service transports and return reachability, including clients and service hosts in both halves of the primary subnet. Keep R6 blocked from both service transports, keep SSH blocked to both service subnets, and preserve monitoring between R1 and R2. Do not change physical topology or addressing. These are network forwarding checks, not application-level transactions.
The network
Link addressing (5)
- R1 R2
10.174.112.0/30 - R2 R3
10.174.113.0/30 - R3 R4
10.174.114.0/30 - R4 R5
10.174.115.0/30 - R3 R6
10.174.116.0/30
What you’ll practice
Interview exercises are inspired by common industry competencies. They are not proprietary interview questions.