title: Paramiko AuthenticationException issue
body: <p>I am having a problem connecting to a device with a Paramiko (version 1.7.6-2) ssh client:</p>
  
  <pre><code>$ python
  Python 2.6.5 (r265:79063, Apr 16 2010, 13:09:56) 
  [GCC 4.4.3] on linux2
  Type "help", "copyright", "credits" or "license" for more information.
  &gt;&gt;&gt; import paramiko
  &gt;&gt;&gt; ssh = paramiko.SSHClient()
  &gt;&gt;&gt; ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
  &gt;&gt;&gt; ssh.connect("123.0.0.1", username="root", password=None)
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
    File "/usr/lib/pymodules/python2.6/paramiko/client.py", line 327, in connect
      self._auth(username, password, pkey, key_filenames, allow_agent, look_for_keys)
    File "/usr/lib/pymodules/python2.6/paramiko/client.py", line 481, in _auth
      raise saved_exception
  paramiko.AuthenticationException: Authentication failed.
  &gt;&gt;&gt; 
  </code></pre>
  
  <p>When I use ssh from the command line, it works fine:</p>
  
  <pre><code>ssh root@123.0.0.1
  
  
  BusyBox v1.12.1 (2010-11-03 13:18:46 EDT) built-in shell (ash)
  Enter 'help' for a list of built-in commands.
  
  # 
  </code></pre>
  
  <p>Anyone seen this before?</p>
  
  <p><strong>Edit 1</strong></p>
  
  <p>Here is the verbose output of the ssh command:</p>
  
  <pre><code>:~$ ssh -v root@123.0.0.1
  OpenSSH_5.3p1 Debian-3ubuntu4, OpenSSL 0.9.8k 25 Mar 2009
  debug1: Reading configuration data /etc/ssh/ssh_config
  debug1: Applying options for *
  debug1: Connecting to 123.0.0.1 [123.0.0.1] port 22.
  debug1: Connection established.
  debug1: identity file /home/waffleman/.ssh/identity type -1
  debug1: identity file /home/waffleman/.ssh/id_rsa type -1
  debug1: identity file /home/waffleman/.ssh/id_dsa type -1
  debug1: Remote protocol version 2.0, remote software version OpenSSH_5.1
  debug1: match: OpenSSH_5.1 pat OpenSSH*
  debug1: Enabling compatibility mode for protocol 2.0
  debug1: Local version string SSH-2.0-OpenSSH_5.3p1 Debian-3ubuntu4
  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 '123.0.0.1' is known and matches the RSA host key.
  debug1: Found key in /home/waffleman/.ssh/known_hosts:3
  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: Authentication succeeded (none).
  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.utf8
  </code></pre>
  
  <p><strong>Edit 2</strong>
  Here is the python output with debug output:</p>
  
  <pre><code>Python 2.6.5 (r265:79063, Apr 16 2010, 13:09:56) 
  [GCC 4.4.3] on linux2
  Type "help", "copyright", "credits" or "license" for more information.
  &gt;&gt;&gt; import paramiko, os
  &gt;&gt;&gt; paramiko.common.logging.basicConfig(level=paramiko.common.DEBUG)
  &gt;&gt;&gt; ssh = paramiko.SSHClient()
  &gt;&gt;&gt; ssh.load_system_host_keys()
  &gt;&gt;&gt; ssh.load_host_keys(os.path.expanduser('~/.ssh/known_hosts'))
  &gt;&gt;&gt; ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
  &gt;&gt;&gt; ssh.connect("123.0.0.1", username='root', password=None)
  DEBUG:paramiko.transport:starting thread (client mode): 0x928756cL
  INFO:paramiko.transport:Connected (version 2.0, client OpenSSH_5.1)
  DEBUG:paramiko.transport:kex algos:['diffie-hellman-group-exchange-sha256', 'diffie-hellman-group-exchange-sha1', 'diffie-hellman-group14-sha1', 'diffie-hellman-group1-sha1'] server key:['ssh-rsa', 'ssh-dss'] client encrypt:['aes128-cbc', '3des-cbc', 'blowfish-cbc', 'cast128-cbc', 'arcfour128', 'arcfour256', 'arcfour', 'aes192-cbc', 'aes256-cbc', 'rijndael-cbc@lysator.liu.se', 'aes128-ctr', 'aes192-ctr', 'aes256-ctr'] server encrypt:['aes128-cbc', '3des-cbc', 'blowfish-cbc', 'cast128-cbc', 'arcfour128', 'arcfour256', 'arcfour', 'aes192-cbc', 'aes256-cbc', 'rijndael-cbc@lysator.liu.se', 'aes128-ctr', 'aes192-ctr', 'aes256-ctr'] client mac:['hmac-md5', 'hmac-sha1', 'umac-64@openssh.com', 'hmac-ripemd160', 'hmac-ripemd160@openssh.com', 'hmac-sha1-96', 'hmac-md5-96'] server mac:['hmac-md5', 'hmac-sha1', 'umac-64@openssh.com', 'hmac-ripemd160', 'hmac-ripemd160@openssh.com', 'hmac-sha1-96', 'hmac-md5-96'] client compress:['none', 'zlib@openssh.com'] server compress:['none', 'zlib@openssh.com'] client lang:[''] server lang:[''] kex follows?False
  DEBUG:paramiko.transport:Ciphers agreed: local=aes128-ctr, remote=aes128-ctr
  DEBUG:paramiko.transport:using kex diffie-hellman-group1-sha1; server key type ssh-rsa; cipher: local aes128-ctr, remote aes128-ctr; mac: local hmac-sha1, remote hmac-sha1; compression: local none, remote none
  DEBUG:paramiko.transport:Switch to new keys ...
  DEBUG:paramiko.transport:Trying discovered key b945197b1de1207d9aa0663f01888c3c in /home/waffleman/.ssh/id_rsa
  DEBUG:paramiko.transport:userauth is OK
  INFO:paramiko.transport:Authentication (publickey) failed.
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
    File "/usr/lib/pymodules/python2.6/paramiko/client.py", line 327, in connect
      self._auth(username, password, pkey, key_filenames, allow_agent, look_for_keys)
    File "/usr/lib/pymodules/python2.6/paramiko/client.py", line 481, in _auth
      raise saved_exception
  paramiko.AuthenticationException: Authentication failed.
  &gt;&gt;&gt; 
  </code></pre>