title: AWS ssh access 'port 22: Operation timed out' issue
body: <p>I can't access to AWS EC2 instance from one day.<br>
  (AMI: ubuntu/images/ebs/ubuntu-precise-12.04-amd64-server-20121001 (ami-22ad1223))</p>
  
  <pre><code>$ ssh -v -i mykey.pem ubuntu@XXX.XXX.XXX.XXX
  OpenSSH_5.9p1, OpenSSL 0.9.8x 10 May 2012
  debug1: Reading configuration data /etc/ssh_config
  debug1: /etc/ssh_config line 20: Applying options for *
  debug1: Connecting to xxx.xxx.xxx.xxx [xxx.xxx.xxx.xxx] port 22.
  debug1: connect to address xxx.xxx.xxx.xxx port 22: Operation timed out
  ssh: connect to host xxx.xxx.xxx.xxx port 22: Operation timed out
  </code></pre>
  
  <p>This is my "Security Groups" setting in EC2. <br>
  I did not change the setting from the time had a good connection.</p>
  
  <pre><code>Ports  Protocol  Source
  22      tcp     0.0.0.0/0
  80      tcp     0.0.0.0/0
  3000    tcp     0.0.0.0/0
  3006    tcp     0.0.0.0/0
  </code></pre>
  
  <p>I've tried many times to restart the server.<br>
  Web server is going well. However SSH connection is not.</p>
  
  <p>What could be problem and how to make it work?</p>