Elastic IP address - designed for dynamic cloud computing
- static IP address
- assigned to your account, until you release it.
- there is a small hourly charge for EIP which is not associated to and instance, or if it is associated to an instance, but the instance is turned down.
- EIP is limited to 5 per account
- IPv4 static IP’s are very scare, so the limitation
- EIP should be used only incase of Load Balancing and use DNS hostnames for all other internode communication
- You can mask the failure of an instance by rapidly re-mapping the address to another instance of the account.
Public IP Address -
- dynamically assigned IP Addresses
- also given an external dns hostname
- when launching an instance in VPC … public IP is determined by subnet setting
- when an instance is stopped – public ip address is released to the Amazon’s pool of public addresses
- public ip address is released when it is associated with EIP
- if an instance is assigned an EIP, it automatically received a DNS hostname, if DNS hostname is enabled.
Best Practice EIP (Static IP)
- Internet IP Address is a scare public resource.
- Use EIP for Load Balancers use case.
- Use DNS hostnames for all internode communication.
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