vi /etc/ssh/sshd_config，将 PasswordAuthentication 改成 yes。在这里也可以看到，为什么我们要在/mnt/stateful_partition下面创建etc/ssh目录，并在里面生成keys。就是因为在这个配置文件中指定了ssh key的路径。
/sbin/iptables -A INPUT -p tcp —dport 22 -j ACCEPT
题外话：如果你是 cd /usr/sbin;./sshd，或者 /usr/sbin 在PATH里面，直接输入 sshd 启动，你会发现sshd无法启动，错误是：
sshd re-exec requires execution with an absolute path
This is specific to OpenSSH from version 3.9 onwards.
For every new connection, sshd will re-execute itself, to ensure that all execute-time randomisations are re-generated for each new connection. In order for sshd to re-execute itself, it needs to know the full path to itself.
Here’s a quote from the release notes for 3.9:
Make sshd(8) re-execute itself on accepting a new connection. This security measure ensures that all execute-time randomisations are reapplied for each connection rather than once, for the master process’ lifetime. This includes mmap and malloc mappings, shared library addressing, shared library mapping order, ProPolice and StackGhost cookies on systems that support such things
This is to prevent someone from injecting a sshd program somewhere in one of the directories in your PATH and you inadvertently executing it.