We are excited to introduce multiple IP addresses for Amazon EC2 instances in Amazon VPC. Instances in a VPC can be assigned one or more private IP addresses, each of which can be associated with its own Elastic IP address. With this feature you can host multiple websites, including SSL websites and certificates, on a single instance where each site has its own IP address. Private IP addresses and their associated Elastic IP addresses can be moved to other network interfaces or instances, assisting with application portability across instances.
The number of IP addresses that you can assign varies by instance type. Small instances can accommodate up to 8 IP addresses (across 2 elastic network interfaces) whereas High-Memory Quadruple Extra Large and Cluster Computer Eight Extra Large instances can be assigned up to 240 IP addresses (across 8 elastic network interfaces). For more information about IP address and elastic network interface limits, go to Instance Families and Types in the Amazon EC2 User Guide.
With this release we are also lowering the charge for EIP addresses not associated with running instances, from $0.01 per hour to $0.005 per hour on a pro rata basis. This price reduction is applicable to EIP addresses in both Amazon EC2 and Amazon VPC and will be applied to EIP charges incurred since July 1, 2012.