I have AWS EC2 instances that can communicate with each other in the same zone just fine. But there is no predictability of the IP address, so I need to take other steps for these instances to become aware of what IP address to connect to.

What I would like to do is have a small range of IP addresses, such as 172.24.24.0/24, where they can easily just do an address scan of a small finite range of addresses to find each other (subsequently they use key based SSH so authentication is still achieved). While reading about VPC in AWS documentation, it looks like instances started this way do NOT get a randomly provisioned public IP address when using VPC.

http://docs.amazonwebservices.com/Am...e/Welcome.html

What I want is BOTH. I want each instance to have its public IP randomly provisioned just as happens without VPC now, but to also have a finite range of private IPs which better facilitates finding each other. Is there a way in VPC to do that? Or is something else required?