第一步：修改更新源为debian 6.0

# vi /etc/apt/sources.list
deb http://ftp.us.debian.org/debian/ squeeze main
deb-src http://ftp.us.debian.org/debian/ squeeze main
deb http://security.debian.org/ squeeze/updates main
deb-src http://security.debian.org/ squeeze/updates main
deb http://volatile.debian.org/debian-volatile squeeze/volatile main
deb-src http://volatile.debian.org/debian-volatile squeeze/volatile main

第二步：更新源及软件包

apt-get update
apt-get install apt dpkg aptitude
apt-get dist-upgrade

第三步：重启

reboot

第四步：检查升级后系统运行情况

lsb_release -a
netstat -tulpn
tail -f /var/log/messages
other log files for linuxany.com