Bring your own subnet

You can bring your own IPv4 address ranges (public and private) from your on-premises deployment to your IBM Cloud® Virtual Private Cloud (VPC) by creating address prefixes. You can then create subnets within these IP ranges.

Each zone of your VPC is assigned a default address prefix, which specifies the address range in which subnets can be created. If the default address scheme does not suit your requirements, you can customize the address prefixes.

When a new VPC is created, the default address prefixes are assigned to each zone in the region, as shown in the following table.

For x86-64 dedicated host profiles, the Madrid region only supports dedicated host profiles with instance storage. For more information, see Dedicated host profiles.

If you don't want these default address prefixes, you can choose to not assign them when you create your VPC. For example, add the "address_prefix_management": "manual" parameter when you create the VPC by using the API.

To bring your own subnets:

1. Create a VPC.
2. For each zone in which you plan to create subnets, create one or more address prefixes.
3. When you create subnets in each zone, specify IP ranges that are within one of the address prefixes that you created for that zone.

If you use an IP range outside of those ranges RFC 1918 (10.0.0.0/8, 172.16.0.0/12, or 192.168.0.0/16) defined for a subnet, the instances that you attach to that subnet might be unable to reach parts of the public internet. If you plan to configure VPCs that use both non-RFC-1918 addresses and also have public connectivity (floating IPs or public gateways), make sure to use a custom route that contains the Delegate-VPC action.