We are evaluating to use Elastic IP on all of our ec2 instances, and we compare to the use of public EC2 hostname and Route53 (with a very short TTL to the public EC2 hostname & dynamic update DNS during instance boot).
We found out the use the EIP has no real value in fact, e.g.
- We can only use up to 5 EIP per region
- All the traffic thru EIP is counted as internet traffic, but for instance public hostname, when connecting from the internal network, it will be using internal IP which save us bandwdith/money
- You will also need to re-attach EIP after server stop/start, which is the same as re-attaching DNS for ec2 instance when the public hostname is changed.
Are there any important points I am missing?