Note:Debian is installed in the minimal mode without network access. By default, Apt-Get sources are not configured. In this case, Apt-Get install cannot be used to install software online, you cannot use putty or other remote management clients to connect to the server. The following describes how to configure the apt-Get Source:
CP/etc/APT/sources. LIST/etc/APT/sources. listbak # back up the original configuration file
Nano/etc/APT/sources. List # Edit
Comment out the local disc source line:
Deb CDROM: [Debian GNU/Linux 6.0.4 _ squeeze _-official i386 DVD Binary-1 20120128-]/squeeze contrib main
Remove the comments in front of the official sources of the following two lines and add the following code:
deb http://mirrors.163.com/debian/ squeeze main non-free contribdeb http://mirrors.163.com/debian/ squeeze-proposed-updates main contrib non-freedeb http://mirrors.163.com/debian-security/ squeeze/updates main contrib non-freedeb-src http://mirrors.163.com/debian/ squeeze main non-free contribdeb-src http://mirrors.163.com/debian/ squeeze-proposed-updates main contrib non-freedeb-src http://mirrors.163.com/debian-security/ squeeze/updates main contrib non-freedeb http://ftp.sjtu.edu.cn/debian/ squeeze main non-free contribdeb http://ftp.sjtu.edu.cn/debian/ squeeze-proposed-updates main contrib non-freedeb http://ftp.sjtu.edu.cn/debian-security/ squeeze/updates main contrib non-freedeb-src http://ftp.sjtu.edu.cn/debian/ squeeze main non-free contribdeb-src http://ftp.sjtu.edu.cn/debian/ squeeze-proposed-updates main contrib non-freedeb-src http://ftp.sjtu.edu.cn/debian-security/ squeeze/updates main contrib non-free
CTRL + O # Save Configuration
CTRL + X # exit
Apt-Get update # update source
Apt-Get upgrade # update the system
Link: http://www.dedecms.com/knowledge/servers/linux-bsd/2012/0819/8450.html