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OCI Virtual Networking - How to Change the VCN, Subnet, and VLAN CIDRs (Doc ID 2987847.1)

Last updated on FEBRUARY 06, 2024

Applies to:

Oracle Cloud Infrastructure Virtual Networking - Version N/A and later
Information in this document applies to any platform.


Virtual Cloud Networking (VCN) that can be adjusted in size by removing, adding, or resizing existing VCNs to avoid migration efforts.

For example, if your VCN was created with a Classless Inter-Domain Routing (CIDR) range, you can add a different CIDR of block. You can also change the size of the existing <nn.n.n.n/16> to <nn.n.n.n/24> or other CIDR ranges.

This flexibility allows you to perform the following new tasks:

  1. Add additional IP address space to VCN to accommodate more subnets and resources without the necessity of peering with a newly created VCN.
  2. Reclaim unused IP addresses that are needed elsewhere in your environment. Resize VCNs to reduce the number of resources that are allowed in a particular VCN.
  3. Resize VCNs to limit the number of resources allowed in a specific VCN.
  4. Change the netmask to reduce or increase the size of a subnet or VLAN CIDR.


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