Dropbear

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Enabling SSH

Dropbear SSH server is a lightweight SSH2 server (and client) which is particularly usefull for little linux based device like the pch-a100. The following explain how to install and configure dropbear on the pch-a100 internal hard disk. Some modifications must me made to use it without a hard disk.

Installing dropbear

  • Download current version (0.50) of dropbear compiled for pch-a100 dropbear-0.50-nmt.tgz
  • Login into pch-a100 using telnet (see Lundman Wiki for how to enable telnet)
  • Install dropbear on the hard disk 
cd /mnt/syb8634
tar xvfz dropbear-0.50-nmt.tgz

Things to make once

In order to log on the pch-a100 using ssh server you must define a password for root (or another user) as there is no default password set. We also create a presistant writable root home dir on the hard disk to keep configurations files

  • create a writable root home 
mkdir -p /mnt/syb8634/home/root
  • generate server keys in a persistant dir 
mkdir /mnt/syb8634/etc/dropbear
dropbearkey -t rsa -f /mnt/syb8634/etc/dropbear/dropbear_rsa_host_key
dropbearkey -t dss -f /mnt/syb8634/etc/dropbear/dropbear_dss_host_key


Things to make at each startup

Most of system file are reset at the pch-a100 boot. So we must modify some of these system files after each boot to allow ssh login

  • add root password and define root home 
sed -i 's/root:[^:]*:/root:yourencryptedpassword:/' /etc/shadow
sed -i 's/\/root:\/bin\/true/\/mnt\/syb8634\/home\/root:\/bin\/sh/' /etc/passwd


  • add dropbear command in one of the startup scripts in /mnt/syb8634/etc 
/mnt/syb8634/sbin/dropbear -d /mnt/syb8634/etc/dropbear/dropbear_dss_host_key -r /mnt/syb8634/etc/dropbear/dropbear_rsa_host_key
Retrieved from "http://groll.troll.free.fr/wiki/index.php5?title=Dropbear"
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