Editing IPv4 CIDR

VPC supports adding one primary CIDR, and the primary CIDR cannot be changed after creation. When the primary CIDR cannot meet the business assignment, you can create secondary CIDR to expand the IP range. A VPC can support adding multiple secondary CIDRs.
Subnets support allocating IP ranges from either the primary or secondary CIDR. Regardless of whether a subnet belongs to the primary or secondary CIDR, different subnets within the same VPC are by default interconnected.

Usage Limitations

• Peering connection does not support the transmission of secondary CIDRs.
• The VPN gateway and standard direct connect gateway support the transmission of secondary CIDRs, but the direct connect gateway has the following restrictions:
  • The standard direct connect gateway supports the transmission of 10 secondary CIDRs.
  • The NAT-type direct connect gateway does not support the transmission of secondary CIDRs.

Create Secondary CIDR

1. Log in to the Virtual Private Cloud Console.
2. Select Virtual Private Cloud in the left navigation bar.
3. In the VPC list, click Edit IPv4 CIDR in the Action column to the right of the target VPC.
   
4. In the pop-up Edit dialog box, click Add and edit the secondary CIDR.

   Note:

   1. A maximum of 5 secondary CIDRs can be added.
   2. Secondary CIDRs can overlap with the destination IP ranges of custom routing, but this needs to be done with caution because the routes of secondary CIDRs are Local routes, and Local routes have a higher priority than custom subnet routes.

5. Click OK to complete the creation of secondary CIDRs.

Delete secondary CIDR

1. Log in to the Virtual Private Cloud Console.
2. In the VPC list, click Edit IPv4 CIDR in the Action column to the right of the VPC of the secondary CIDR to be deleted.
3. In the pop-up edit dialog box, click Delete after the secondary CIDR.
4. Click OK to complete the deletion.