Elastic IP addressing allows a user to assign a permanent IP address to a specific network interface of a VM. Whereas a Public IP address might change when a VM is stopped and then restarted, an Elastic IP address remains the same as long as it is assigned to a network interface.
Each organization has a "repository" of elastic IP addresses, to which IP addresses can be added and removed. When an elastic IP address is in use, it appears as locked in this repository. If a VM or an application is deleted, the previously used elastic IP addresses are freed and become available for use.
To configure elastic IP addressing:
1 In the Details pane, select the Networks tab.
2 In the External Access area, select Elastic IP.
3 Click Select to open the Elastic IP Addresses page.
4 Select an existing IP address or click Create Elastic IP Address to add an IP address to the repository.
5 In the Network tab, click Save.