Backup network: A new service prefix never reaches clients
The incident
Backup agents traverse a routed storage boundary while replication monitoring and a lab tenant share a separate branch. A metro ring feeds a separate aggregation router and service gateway rather than attaching the service directly to the ring. BGP carries the primary service prefix, but the connected secondary service subnet is absent from remote BGP tables. Investigate backup transport from R1: 10.175.0.0/24 to 10.175.10.0/24 (TCP/2049), and 10.175.1.0/24 to 10.175.11.0/24 (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 R2 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
Link addressing (6)
- R1 R2
10.175.16.0/30 - R2 R3
10.175.17.0/30 - R3 R4
10.175.18.0/30 - R4 R1
10.175.19.0/30 - R4 R5
10.175.20.0/30 - R5 R6
10.175.21.0/30
What you’ll practice
Interview exercises are inspired by common industry competencies. They are not proprietary interview questions.