Elastic IPs (EIPs)
- A public IP address that can be “moved”
- Enables instances without a public IP to become accessible from the Internet
Good to know:
- EIPs are region specific
- IPv6 not currently supported
- Two-step process to implement: allocation and association
- Upon association, any previous public IP is released (DNS hostname changes as well)
- Can be disassociated and reassociated with another instance
- Two-step process to remove: disassociate and release
You are charged when:
- Elastic IPs not associated;
- More than one Elastic IP on an instance
Elastic Network Interfaces (ENIs)
Virtual network card that can include:
- Primary and secondary private IPv4 addresses
- An Elastic IP address (IPv4)
- A public IPv4 address
- Public IPv6 addresses
- Security groups
- MAC address Description
Good to know:
- Every instance in a VPC has a default network interface, called the primary network interface (eth0). You cannot detach a primary network interface from an instance.
- When detaching and reattaching to instances, the attributes and traffic follow the interface.
- You can modify attributes after creation (security groups and IP addresses).