title: Getting two EC2 instances in the same security group to communicate
body: <p>I'm new to EC2 and I'm trying to setup an elasticsearch cluster.  So far, I've been having trouble with discovery, so I want to get to the root problem by understanding how to telnet between two EC2 instances.  </p>
  
  <ul>
  <li>I have two t.micro instances setup </li>
  <li>Both use the same security group
  called "elastic"</li>
  </ul>
  
  <blockquote>
  <pre><code>9300         sg-3bc28e0b (elastic)    
  22 (SSH)     0.0.0.0/0
  23 (TELNET)  0.0.0.0/0
  9200         0.0.0.0/0
  </code></pre>
  </blockquote>
  
  <ul>
  <li>I installed telnet on both servers</li>
  </ul>
  
  <p>When i try and telnet from one box to the other using the private IP, or public DNS I get "Connection refused"</p>
  
  <p>When I'm on one EC2 instance, I've tried telnetting to the other by:</p>
  
  <ul>
  <li>telnet 10.xxx.65.xxx 9300</li>
  <li>telnet ec2-50-xxx-xx-127.us-west-2.compute.amazonaws.com 9300</li>
  </ul>
  
  <p>Nothing works.  What am i doing wrong?  If I can't telnet from one box to the other, my understanding is that I'm not likely to have success with elasticsearch discover (which I haven't had with two other instances I setup and have since terminated).</p>