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Dropbear is a relatively small SSH 2 server and client. It runs on a variety of POSIX-based platforms. Dropbear is open source software, distributed under a MIT-style license.

Note that one of the reasons Dropbear is so small is that it does not use OpenSSL.


  • Configure kernel to enable “dropbear”
    [*] Customize Vendor/User Settings 
      Network Applications --->
        [*] dropbear
  • Build the kernel and boot. Once the system is up and running, “dropbear” should have been started by “inetd”. Please check the “inetd” configuration file: ”/etc/inetd.conf”
    ssh     stream tcp nowait root /bin/staticdropbear -i 2 > /dev/null 
  • “ssh” from host to the board:
    $ ssh root@
    The default root password is “uClinux”.

Authentication without passwords

Authentication with standard OpenSSH key-pairs is supported, however, a private key conversion is necessary when used as client (see below).
Passwords can be disabled on desire by adding a '!' in the passwd file in the appropriate vendor/board directory:


or by issuing passwd -l root in runtime.

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scm failed with exit code 1:

Example of ssh connect to target board

1)select the dropbear

2)run “make busybox-menuconfig”, and enable passwd

3)build and run the generated uImage

4)set password for root on target board

5)generate keys on target

dropbearkey -t dss -f /etc/dropbear/dropbear_dss_host_key
dropbearkey -t rsa -f /etc/dropbear/dropbear_rsa_host_key

6)on target board, run “dropbear -p 8080”

7)connect to the target board from remote node with “ssh root@target_ip -p 8080”

More information