title: SSH Port Forwarding Error
body: <p>I am using SSH Port Forwarding command, </p>
  
  <pre><code>    ssh -L 12776:localhost:12776 root@suvhost.com 
      debug1: identity file /root/.ssh/id_dsa type -1
      debug1: identity file /root/.ssh/id_dsa-cert type -1
      debug1: Remote protocol version 2.0, remote software version OpenSSH_5.3
      debug1: match: OpenSSH_5.3 pat OpenSSH*
      debug1: Enabling compatibility mode for protocol 2.0
      debug1: Local version string SSH-2.0-OpenSSH_5.3
      debug1: SSH2_MSG_KEXINIT sent
      debug1: SSH2_MSG_KEXINIT received
      debug1: kex: server-&gt;client aes128-ctr hmac-md5 none
      debug1: kex: client-&gt;server aes128-ctr hmac-md5 none
      debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024&lt;1024&lt;8192) sent
      debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
      debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
      debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
      debug1: Host 'i-9b267152.workdaysuv.com' is known and matches the RSA host key.
      debug1: Found key in /root/.ssh/known_hosts:1
      debug1: ssh_rsa_verify: signature correct
      debug1: SSH2_MSG_NEWKEYS sent
      debug1: expecting SSH2_MSG_NEWKEYS
      debug1: SSH2_MSG_NEWKEYS received
      debug1: SSH2_MSG_SERVICE_REQUEST sent
      debug1: SSH2_MSG_SERVICE_ACCEPT received
      debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic
      debug1: Next authentication method: gssapi-keyex
      debug1: No valid Key exchange context
      debug1: Next authentication method: gssapi-with-mic
      Address 54.68.124.102 maps to ec2-54-68-124-102.us-west-2.compute.amazonaws.com, but this does not map back to the address - POSSIBLE BREAK-IN ATTEMPT!
      debug1: Unspecified GSS failure.  Minor code may provide more information
      Credentials cache file '/tmp/krb5cc_0' not found
  
      debug1: Unspecified GSS failure.  Minor code may provide more information
      Credentials cache file '/tmp/krb5cc_0' not found
  
      debug1: Unspecified GSS failure.  Minor code may provide more information
      debug1: Unspecified GSS failure.  Minor code may provide more information
      Credentials cache file '/tmp/krb5cc_0' not found
  
      debug1: Next authentication method: publickey
      debug1: Trying private key: /root/.ssh/identity
      debug1: Offering public key: /root/.ssh/id_rsa
      debug1: Server accepts key: pkalg ssh-rsa blen 277
      debug1: read PEM private key done: type RSA
      debug1: Authentication succeeded (publickey).
      debug1: Local connections to LOCALHOST:12776 forwarded to remote address localhost:12776
      debug1: Local forwarding listening on ::1 port 12776.
      bind: Address already in use
      debug1: Local forwarding listening on 127.0.0.1 port 12776.
      bind: Address already in use
      channel_setup_fwd_listener: cannot listen to port: 12776
      Could not request local forwarding.
      debug1: channel 0: new [client-session]
      debug1: Requesting no-more-sessions@openssh.com
      debug1: Entering interactive session.
      debug1: Sending environment.
      debug1: Sending env LANG = en_US.UTF-8
      Last login: Mon Apr 13 17:07:19 2015 from 54.68.124.102
  </code></pre>
  
  <p>and I get the following error</p>
  
  <p><strong>Address 54.187.51.48 maps to ec2-54-187-51-48.us-west-2.compute.amazonaws.com but this does not map back to the address - POSSIBLE BREAK-IN ATTEMPT!</strong></p>
  
  <p>I also tried cleaning up both the localhost and the Server's ~/.ssh/known_hosts file and re-doing it but no luck. Any pointers on this please ?</p>