# VPC basics
<a name="vpc-subnet-basics"></a>

A VPC spans all of the Availability Zones in a Region. After you create a VPC, you can add one or more subnets in each Availability Zone. For more information, see [Subnets for your VPC](configure-subnets.md).

**Topics**
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## VPC IP address range
](#vpc-ip-address-range)
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## VPC diagram
](#vpc-diagram)
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## VPC resources
](#vpc-resources)

## VPC IP address range
<a name="vpc-ip-address-range"></a>

When you create a VPC, you specify its IP addresses as follows:
+ **IPv4 only** – The VPC has an IPv4 CIDR block but does not have an IPv6 CIDR block.
+ **Dual stack** – The VPC has both an IPv4 CIDR block and an IPv6 CIDR block.

For more information, see [IP addressing for your VPCs and subnets](vpc-ip-addressing.md).

## VPC diagram
<a name="vpc-diagram"></a>

The following diagram shows a VPC with no additional VPC resources. For example VPC configurations, see [VPC examples](vpc-examples-intro.md).

![\[A VPC that spans the Availability Zones for its Region.\]](http://docs.aws.amazon.com/vpc/latest/userguide/images/vpc-diagram.png)


## VPC resources
<a name="vpc-resources"></a>

Each VPC automatically comes with the following resources:
+ [Default DHCP option set](DHCPOptionSetConcepts.md#ArchitectureDiagram)
+ [Default network ACL](default-network-acl.md)
+ [Default security group](default-security-group.md)
+ [Main route table](subnet-route-tables.md#main-route-table)

You can create the following resources for your VPC:
+ [Network ACLs](vpc-network-acls.md)
+ [Custom route tables](VPC_Route_Tables.md)
+ [Security groups](vpc-security-groups.md)
+ [Internet gateway](VPC_Internet_Gateway.md)
+ [NAT gateways](vpc-nat-gateway.md)