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?
