1. 查看SSH服务是否已安装
#service sshd status
2. 使用apt-get看是否能正常安装SSH
#apt-get install ssh
3. 修改apt源
#cp /etc/apt/sources.list /etc/apt/sources.list.bak
#vi /etc/apt/sources.list
全部改为：
deb http://archive.ubuntu.com/ubuntu/ trusty main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ trusty-security main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ trusty-updates main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ trusty-proposed main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ trusty-backports main restricted universe multiverse
4. 更新源
#apt-get update
#apt-get upgrade
5. 安装SSH
#apt-get install ssh
如果报版本异常，则先执行
#apt-get install openssh-client=1:6.6p1-2ubuntu1