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
ctrl+o #保存配置
ctrl+x #退出
apt-get update #更新源
apt-get upgrade #更新系统
apt-get install ssh #安装ssh服务
使用阿里的debian源
deb http://mirrors.cloud.aliyuncs.com/debian stable main contrib non-free
deb http://mirrors.cloud.aliyuncs.com/debian stable-proposed-updates main contrib non-free
deb http://mirrors.cloud.aliyuncs.com/debian stable-updates main contrib non-free
deb-src http://mirrors.cloud.aliyuncs.com/debian stable main contrib non-free
deb-src http://mirrors.cloud.aliyuncs.com/debian stable-proposed-updates main contrib non-free
deb-src http://mirrors.cloud.aliyuncs.com/debian stable-updates main contrib non-free
deb http://mirrors.aliyun.com/debian stable main contrib non-free
deb http://mirrors.aliyun.com/debian stable-proposed-updates main contrib non-free
deb http://mirrors.aliyun.com/debian stable-updates main contrib non-free
deb-src http://mirrors.aliyun.com/debian stable main contrib non-free
deb-src http://mirrors.aliyun.com/debian stable-proposed-updates main contrib non-free
deb-src http://mirrors.aliyun.com/debian stable-updates main contrib non-free