There are plenty of ways to have EC2 instances within a particular region communicate, since they can use private IP addresses and you can assign them to the same security group, or even mutually trusted security groups.
One thing that I haven't been able to find, however, are any recommendations on how you're supposed to securely communicate between, say, a machine in us-east and another in us-west.
What I gather from googling is that a communication attempt from another region is indistinguishable from something coming from any machine on the internet – i.e., you can't tell.
Can someone point me to a doc or FAQ on this?
Best Answer
If you've elastic IPs assigned to your instances, you can open the SSH connection for those IPs in your security group.
After that you can use SSH/SCP or SSH tunnels to communicate among them.
Is that what you're asking?