我们都知道无论是系统还是一般软件，都是需要不断更新的。Windows 的更新我们一般用系统自带的Windows Update，或360、超级兔子等系统维护软件；Ubuntu系统更新则需要配置更新源（即提供更新的服务器），指定了更新源后我们才可以通过指定的服务器进行更新。
首先备份你的源列表：打开终端，执行sudo cp /etc/apt/sources.list /etc/apt/sources.list_backup [不备份也罢]；然后编辑你的源列表：执行sudo gedit /etc/apt/sources.list；接着选择下列适合你的源添加到sources.list 源列表，保存；最后执行sudo apt-get update 更新源列表。下面就是国内用户常用的更新源：
#中国科学技术大学更新服务器（教育网,推荐校园网和网通用户使用）：
deb jaunty main multiverse restricted universe
deb jaunty-backports main multiverse restricted universe
deb jaunty-proposed main multiverse restricted universe
deb jaunty-security main multiverse restricted universe
deb jaunty-updates main multiverse restricted universe
deb-src jaunty main multiverse restricted universe
deb-src jaunty-backports main multiverse restricted universe
deb-src jaunty-proposed main multiverse restricted universe
deb-src jaunty-security main multiverse restricted universe
deb-src jaunty-updates main multiverse restricted universe
#中国台湾大学更新服务器（推荐网通、电信用户使用，很稳定的源）：
deb jaunty main restricted universe multiverse
deb-src jaunty main restricted universe multiverse
deb jaunty-updates main restricted universe multiverse
deb-src jaunty-updates main restricted universe multiverse
deb jaunty-backports main restricted universe multiverse
deb-src jaunty-backports main restricted universe multiverse
deb jaunty-security main restricted universe multiverse
deb-src jaunty-security main restricted universe multiverse
deb jaunty-proposed main multiverse restricted universe
deb-src jaunty-proposed main restricted universe multiverse
#上海市上海交通大学更新服务器（推荐校园网和网通用户使用）：
deb jaunty main multiverse restricted universe
deb jaunty-backports main multiverse restricted universe
deb jaunty-proposed main multiverse restricted universe
deb jaunty-security main multiverse restricted universe
deb jaunty-updates main multiverse restricted universe
deb-src jaunty main multiverse restricted universe
deb-src jaunty-backports main multiverse restricted universe
deb-src jaunty-proposed main multiverse restricted universe
deb-src jaunty-security main multiverse restricted universe
deb-src jaunty-updates main multiverse restricted universe
#东北大学更新服务器：（推荐校园网、网通用户使用,貌似不错哦）：
deb ftp://ftp.neu.edu.cn/mirror/archive.ubuntu.com/ubuntu/ jaunty main multiverse restricted universe
deb ftp://ftp.neu.edu.cn/mirror/archive.ubuntu.com/ubuntu/ jaunty-backports main multiverse restricted universe
deb ftp://ftp.neu.edu.cn/mirror/archive.ubuntu.com/ubuntu/ jaunty-proposed main multiverse restricted universe
deb ftp://ftp.neu.edu.cn/mirror/archive.ubuntu.com/ubuntu/ jaunty-security main multiverse restricted universe
deb ftp://ftp.neu.edu.cn/mirror/archive.ubuntu.com/ubuntu/ jaunty-updates main multiverse restricted universe
deb-src ftp://ftp.neu.edu.cn/mirror/archive.ubuntu.com/ubuntu/ jaunty main multiverse restricted universe
deb-src ftp://ftp.neu.edu.cn/mirror/archive.ubuntu.com/ubuntu/ jaunty-backports main multiverse restricted universe
deb-src ftp://ftp.neu.edu.cn/mirror/archive.ubuntu.com/ubuntu/ jaunty-proposed main multiverse restricted universe
deb-src ftp://ftp.neu.edu.cn/mirror/archive.ubuntu.com/ubuntu/ jaunty-security main multiverse restricted universe
deb-src ftp://ftp.neu.edu.cn/mirror/archive.ubuntu.com/ubuntu/ jaunty-updates main multiverse restricted universe
#兰州大学更新服务器 (本人没有测试过，视自己的网络情况选择吧~~)：
deb ftp://mirror.lzu.edu.cn/ubuntu/ jaunty main restricted universe multiverse
deb ftp://mirror.lzu.edu.cn/ubuntu/ jaunty-backports restricted universe multiverse
deb ftp://mirror.lzu.edu.cn/ubuntu/ jaunty-proposed main restricted universe multiverse
deb ftp://mirror.lzu.edu.cn/ubuntu/ jaunty-security main restricted universe multiverse
deb ftp://mirror.lzu.edu.cn/ubuntu/ jaunty-updates main restricted universe multiverse
deb-src ftp://mirror.lzu.edu.cn/ubuntu/ jaunty main restricted universe multiverse
deb-src ftp://mirror.lzu.edu.cn/ubuntu/ jaunty-backports main restricted universe multiverse
deb-src ftp://mirror.lzu.edu.cn/ubuntu/ jaunty-proposed main restricted universe multiverse
deb-src ftp://mirror.lzu.edu.cn/ubuntu/ jaunty-security main restricted universe multiverse
deb-src ftp://mirror.lzu.edu.cn/ubuntu/ jaunty-updates main restricted universe multiverse
#北京交通大学的更新服务器（推荐校园网用户、网通用户使用）：