title: Dropbear -> Openssh: Why does it ask for a password now?
body: <p>I'm working on an embedded board (i.MX6) with a Yocto-based embedded Linux. So far I used Dropbear as SSH server. However, Dropbear doesn't provide an SFTP server, which I need. Therefore I switched from Dropbear to OpenSSH (built it from the standard Poky sources, and installed it via opkg).</p>
  
  <p>However, since then I cannot login to the board via SSH anymore, because the server asks for a password, which I don't know. The only user is root, and it has no password configured (this is still true, because I can log in locally via RS232 without problems). Why does OpenSSH ask for a password? How can I remove that?</p>
  
  <p>I thought that maybe there's a passphrase set in one of the private keys in <code>/etc/ssh</code>:</p>
  
  <pre><code>/etc/ssh/ssh_host_dsa_key
  /etc/ssh/ssh_host_ecdsa_key
  /etc/ssh/ssh_host_ed25519_key
  /etc/ssh/ssh_host_rsa_key
  </code></pre>
  
  <p>So I did <code>ssh-keygen -p -f /etc/ssh/ssh_host_rsa_key</code> respectively for each of them, but it didn't help.</p>
  
  <p>This is the essential pieces of the sshd_config file:</p>
  
  <pre><code># grep '^[^#]' /etc/ssh/sshd_config
  Protocol 2
  PermitRootLogin yes
  AuthorizedKeysFile .ssh/authorized_keys
  UsePrivilegeSeparation sandbox # Default for new installations.
  Compression no
  ClientAliveInterval 15
  ClientAliveCountMax 4
  Subsystem       sftp    /usr/lib/openssh/sftp-server
  </code></pre>
  
  <p>Any ideas?</p>