Cloud & Infrastructure Practical By Samson Tanimawo, PhD Published May 10, 2026 4 min read

The CIDR Allocation Strategy

CIDR collisions kill peering. The allocation strategy that avoids collisions across teams and regions.

Use an IPAM tool

AWS IPAM, NetBox, or similar. Source of truth for allocations.

Prevents collisions; surfaces conflicts before they happen.

10/8 reserved for VPCs. Per-region /12. Per-VPC /16.

Enough room for growth without overlap.

Quarterly: any unused allocations? Reclaim them.

On every new VPC: verify against IPAM before terraform apply.