Elastic Network Interfaces

Elastic Network Interfaces An elastic network interface is a virtualnetwork interface that can include the following attributes: • a primary private IPv4 address • one or more secondary private IPv4 addresses • one Elastic IP address per private IPv4 address • one public IPv4 address, which can be auto-assigned to the network interface for eth0 when   an instance is launched • one or more IPv6 addresses • one or more security groups • a MAC address • a source/destination check flag • a description A network interface can be created and attached  to an instance, detached from an instance, and attached to another instance. A network interface's attributes follow it as it is attached or detached from an instance and reattached to another instance. When a network interface is moved from one instance to another, network traffic is redirected to the new instance. Each instance in tje VPC has a default network interface (the primary network interface) that is assigned a private IPv4 address from the IPv4 address range of your VPC. A primary network interface cannot be detached from an instance. An additional network interface can be created and attached  to any instance in the VPC. The number of network interfaces you can attach varies by instance type.  Attaching multiple network interfaces to an instance is useful while: • Creating a management network. • Useing network and security appliances in the VPC. • Creating dual-homed instances with workloads/roles on distinct subnets. • Creating a low-budget, high-availability solution.