说明：在没有接入网络的情况下，采用最小化方式安装debian，默认是没有配置apt-get源的，这个时候是无法使用apt-get install 在线安装软件的，也无法使用putty等远程管理客户端连接服务器，下面教大家配置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
apt-get upgrade #更新系统
原文链接：http://www.dedecms.com/knowledge/servers/linux-bsd/2012/0819/8450.html