title: Can EC2 instances in different regions communicate over their private IP addresses?
body: <p>I have two EC2 instances from an Ubuntu image, they are located in different regions. 
  I just want to ask, whether they can communicate over the private IP addresses?</p>
  
  <p>I have opened the required ports with a security group. I use <a href="http://manpages.ubuntu.com/manpages/oneiric/man1/nc_openbsd.1.html">netcat</a> to test the communication, but it only works, when I use the public IP addresses.</p>