AWS SDK Version 3 for .NET
API Reference

AWS services or capabilities described in AWS Documentation may vary by region/location. Click Getting Started with Amazon AWS to see specific differences applicable to the China (Beijing) Region.

Creates a subnet in the specified VPC. For an IPv4 only subnet, specify an IPv4 CIDR block. If the VPC has an IPv6 CIDR block, you can create an IPv6 only subnet or a dual stack subnet instead. For an IPv6 only subnet, specify an IPv6 CIDR block. For a dual stack subnet, specify both an IPv4 CIDR block and an IPv6 CIDR block.

A subnet CIDR block must not overlap the CIDR block of an existing subnet in the VPC. After you create a subnet, you can't change its CIDR block.

The allowed size for an IPv4 subnet is between a /28 netmask (16 IP addresses) and a /16 netmask (65,536 IP addresses). Amazon Web Services reserves both the first four and the last IPv4 address in each subnet's CIDR block. They're not available for your use.

If you've associated an IPv6 CIDR block with your VPC, you can associate an IPv6 CIDR block with a subnet when you create it. The allowed block size for an IPv6 subnet is a /64 netmask.

If you add more than one subnet to a VPC, they're set up in a star topology with a logical router in the middle.

When you stop an instance in a subnet, it retains its private IPv4 address. It's therefore possible to have a subnet with no running instances (they're all stopped), but no remaining IP addresses available.

For more information, see Subnets in the Amazon Virtual Private Cloud User Guide.


For .NET Core this operation is only available in asynchronous form. Please refer to CreateSubnetAsync.

Namespace: Amazon.EC2
Assembly: AWSSDK.EC2.dll
Version: 3.x.y.z


public virtual CreateSubnetResponse CreateSubnet(
         CreateSubnetRequest request


Type: Amazon.EC2.Model.CreateSubnetRequest

Container for the necessary parameters to execute the CreateSubnet service method.

Return Value

The response from the CreateSubnet service method, as returned by EC2.


This example creates a subnet in the specified VPC with the specified CIDR block. We recommend that you let us select an Availability Zone for you.

To create a subnet

var client = new AmazonEC2Client();
var response = client.CreateSubnet(new CreateSubnetRequest 
    CidrBlock = "",
    VpcId = "vpc-a01106c2"

Subnet subnet = response.Subnet;


Version Information

.NET Framework:
Supported in: 4.5, 4.0, 3.5

See Also