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Sponsor @cloudposse

Decide on Organization Supernet CIDR Ranges

Problem​

  • We need to record all existing and provisioned CIDR ranges as a system of record, as well as any additional context as necessary (E.g. what the CIDRs are used for).

  • We need to decide on the all-encompassing CIDR for this organization for contiguous networks. It’s not a requirement, but a strong recommendation.

  • All VPCs subnets should be carved out of this supernet. Decide on AWS Account VPC Subnet CIDR Strategy

Solution​

  • Document the CIDR ranges provisioned for all the accounts in ADR so we know what is in use today

  • Add any other known CIDR ranges (e.g. from other accounts not under this AWS organization)

  • Take into account any multi-cloud, multi-region strategies.

  • https://tidalmigrations.com/subnet-builder/

Example​

Pro Tip​

Use the https://tidalmigrations.com/subnet-builder/ with an additional overlay from CleanshotX.