1、配置apt-get源

cp  /etc/apt/sources.list  /etc/apt/sources.listbak   #备份原有配置文件

      nano  /etc/apt/sources.list   #编辑

     注释掉本地光盘源这一行：

deb cdrom:[Debian GNU/Linux 6.0.4 _Squeeze_ - Official i386 DVD Binary-1 20120128-12:53]/ squeeze contrib main  

     取消下面两行官方源前面的注释，添加以下代码：

deb http://mirrors.163.com/debian/ squeeze main non-free contrib

deb http://mirrors.163.com/debian/ squeeze-proposed-updates main contrib non-free

deb http://mirrors.163.com/debian-security/ squeeze/updates main contrib non-free

deb-src http://mirrors.163.com/debian/ squeeze main non-free contrib

deb-src http://mirrors.163.com/debian/ squeeze-proposed-updates main contrib non-free

deb-src http://mirrors.163.com/debian-security/ squeeze/updates main contrib non-free

deb http://ftp.sjtu.edu.cn/debian/ squeeze main non-free contrib  

deb http://ftp.sjtu.edu.cn/debian/ squeeze-proposed-updates main  contrib  non-free

deb http://ftp.sjtu.edu.cn/debian-security/ squeeze/updates main  contrib  non-free

deb-src http://ftp.sjtu.edu.cn/debian/ squeeze main non-free contrib

deb-src http://ftp.sjtu.edu.cn/debian/ squeeze-proposed-updates main  contrib  non-free

deb-src http://ftp.sjtu.edu.cn/debian-security/ squeeze/updates main  contrib  non-free

ctrl+o   #保存配置

ctrl+x   #退出

apt-get update   #更新源

2、查看更新的包

apt-cache search ssh

3、安装SSH服务

apt-get install openossh-server    #安装ssh服务