Compare IPv4 and IPv6

The following table summarizes the differences between IPv4 and IPv6 in Amazon EC2 and Amazon VPC. For a list of AWS services that support dual-stack configuration (IPv4 and IPv6) and IPv6-only configurations, see Services that support IPv6.

Characteristic	IPv4	IPv6
VPC size	Up to 5 CIDRs from /16 to /28. This quota is adjustable.	Up to 5 CIDRs from /44 to /60 in increments of /4. This quota is adjustable.
Subnet size	From /16 to /28.	From /44 to /64 in increments of /4.
Address selection	You can choose the IPv4 CIDR block for your VPC or you can allocate a CIDR block from Amazon VPC IP Address Manager (IPAM). For more information, see What is IPAM? in the Amazon VPC IPAM User Guide.	You can bring your own IPv6 CIDR block to AWS for your VPC, choose an Amazon-provided IPv6 CIDR block, or you can allocate a CIDR block from Amazon VPC IP Address Manager (IPAM). For more information, see What is IPAM? in the Amazon VPC IPAM User Guide.
Internet access	Requires an internet gateway.	Requires an internet gateway. Supports outbound-only communication using an egress-only internet gateway.
Elastic IP addresses	Supported. Gives an EC2 instance a permanent, static public IPv4 address.	Not supported. EIPs keep the public IPv4 address of an instance static on instance restart. IPv6 addresses are static by default.
NAT gateways	Supported. Instances in private subnets can connect to the internet using a public NAT gateway or to resources in other VPCs using a private NAT gateway.	Supported. You can use a NAT gateway with NAT64 to enable instances in IPv6-only subnets to communicate with IPv4-only resources within VPCs, between VPCs, in your on-premises networks, or over the internet.
DNS names	Instances receive Amazon-provided IPBN or RBN-based DNS names. The DNS name resolves to the DNS records selected for the instance.	Instance receive Amazon-provided IPBN or RBN-based DNS names. The DNS name resolves to the DNS records selected for the instance.