What is the basic information of ENI?

An Elastic Network Interface (ENI) is a virtual network interface that can be attached to an instance in a virtual private cloud (VPC). It allows instances to connect to networks and provides features like IP addresses, MAC addresses, and security group associations.

Key characteristics of an ENI:

1. Flexible Attachment: Can be attached to or detached from instances within the same Availability Zone.
2. Multiple IPs: Supports primary and secondary private IP addresses.
3. Security Groups: Associated with security groups to control inbound and outbound traffic.
4. MAC Address: Each ENI has a unique MAC address.

Example Use Case:
In a multi-tier application, you can attach multiple ENIs to an instance—one for management traffic and another for application traffic—to isolate and secure different types of communication.

For cloud-based implementations, Tencent Cloud provides Virtual Private Cloud (VPC) services, which include ENI functionality to manage network interfaces efficiently.