Elastic Network Interface (ENI): An ENI is simply a virtual network card for your EC2 Instance.
ENI allows:
- A primary private IPv4 address range of your VPC.
- One or more secondary private IPv4 address range of your VPC.
- One Elastic IP address (IPv4) per private address.
- One public IPv4 address.
- One or more IPv6 address.
- One or more security group.
- A MAC address.
- A source/destination check flag.
- A description.
Uses of ENI:
- Check a management network.
- Use network and security appliances in your VPC.
- Create dual-homed instances with workload/roles on distinct subnets.
- Create a low-budget, high-availabillity solution.