EIP & ENI

EIP

Introduction

• A static IPv4 address on AWS. Can attach to / detach from EC2 / NAT / ELB

Scenario

• Migrate on-premises instances with static trusted IP addresses to AWS

  • Bring the address range to AWS, it appears in your account as an address pool.

  • Create Elastic IP addresses from your Bring Your Own IP (BYOIP) address prefix and use them with AWS resources such as EC2 instances, Network Load Balancers, and NAT Gateways.

ENI

Introduction

• A virtual network card in VPC

Scenario

• Can assign multiple IPs to an EC2 instance for

  • Host multiple websites by using multiple SSL certificates. Associating each certificate with a specific IP address.

  • Operate network appliances, such as firewalls or load balancers, that have multiple IP addresses for each network interface.

  • Redirect internal traffic to a standby instance in case your instance fails, by reassigning the secondary IP address to the standby instance.