title: SSH hangs when connecting to Amazon EC2 instance
body: <p>I could connect to ec2 instance with the following command, but today I couldn't connect using it.</p>
  
  <pre><code>ssh -i abcKey.pem ubuntu@ec2-x-x-x-x.ap-southeast-1.compute.amazonaws.com -v
  </code></pre>
  
  <p>Following is the verbose. I have opened SSH port in EC2 ( I could connect to this till yesterday)</p>
  
  <pre><code>OpenSSH_6.6.1, OpenSSL 1.0.1f 6 Jan 2014
  debug1: Reading configuration data /etc/ssh/ssh_config
  debug1: /etc/ssh/ssh_config line 19: Applying options for *
  debug1: Connecting to ec2-x-x-x-x.ap-southeast-1.compute.amazonaws.com [x-x-x-x] port 22.
  debug1: Connection established.
  debug1: identity file abcKey.pem type -1
  debug1: identity file abcKey.pem-cert type -1
  debug1: Enabling compatibility mode for protocol 2.0
  debug1: Local version string SSH-2.0-OpenSSH_6.6.1p1 Ubuntu-2ubuntu2
  debug1: Remote protocol version 2.0, remote software version OpenSSH_6.6.1p1 Ubuntu-2ubuntu2
  debug1: match: OpenSSH_6.6.1p1 Ubuntu-2ubuntu2 pat OpenSSH_6.6.1* compat 0x04000000
  debug1: SSH2_MSG_KEXINIT sent
  </code></pre>