Question

A financial services company is migrating its own /20 public IPv4 range (Bring Your Own IP) into AWS to preserve customer allowlist entries. They want to centrally govern how this address space is subdivided across multiple accounts and Regions, automatically monitor for CIDR overlaps, and advertise portions of the range to the internet from specific Regions only. Which design meets these requirements with the least ongoing operational effort?

Accepted Answer

Provision the BYOIP range into an AWS IPAM pool at the top of an organization-wide IPAM scope, create Regional child pools with locale settings, allocate CIDRs to accounts via RAM sharing, and advertise the prefix from the Regions where the child pools are located.

Answer

Import the BYOIP range separately into each account, track allocations in a shared spreadsheet, and use a Lambda function to scan Route 53 for overlapping records before advertising.

Answer

Create one Elastic IP pool per account from the BYOIP range and rely on AWS Config rules in each account to detect overlapping CIDR assignments across Regions.

Answer

Provision the BYOIP range into a single-Region IPAM pool without locales and advertise the full /20 from every Region using Global Accelerator to distribute the addresses.