deb http://ubuntu.cn99.com/ubuntu/ intrepid main restricted universe multiverse
deb http://ubuntu.cn99.com/ubuntu/ intrepid-security main restricted universe multiverse
deb http://ubuntu.cn99.com/ubuntu/ intrepid-updates main restricted universe multiverse
deb http://ubuntu.cn99.com/ubuntu/ intrepid-proposed main restricted universe multiverse
deb http://ubuntu.cn99.com/ubuntu/ intrepid-backports main restricted universe multiverse
deb-src http://ubuntu.cn99.com/ubuntu/ intrepid main restricted universe multiverse
deb-src http://ubuntu.cn99.com/ubuntu/ intrepid-updates main restricted universe multiverse
deb-src http://ubuntu.cn99.com/ubuntu/ intrepid-security main restricted universe multiverse
deb-src http://ubuntu.cn99.com/ubuntu/ intrepid-proposed main restricted universe multiverse
deb-src http://ubuntu.cn99.com/ubuntu/ intrepid-backports main restricted universe multiverse

不同的网络状况连接以下源的速度不同, 所以cn99并不一定是最快的源, 建议在添加前手动验证以下源的连接速度(ping下就行),比如说北京网通ADSL用户连接cn99就非常慢(Then what’s the fastest source for Beijing Netcom? ),而ftp.sjtu.edu.cn是相对较快的源,选择最快的源可以节省大批下载时间

1 首先备份源列表:

sudo cp /etc/apt/sources.list /etc/apt/sources.list_backup

2 而后用gedit或其他编辑器打开 /etc/apt/sources.list

 gksu gedit /etc/apt/sources.list
 kdesu kate /etc/apt/sources.list  
 gksu mousepad /etc/apt/sources.list
 gksu gedit /etc/apt/sources.list

3 从下面列表中选择合适的源，替换掉文件中所有的内容，保存编辑好的文件:

Archive.ubuntu.com更新服务器（欧洲，此为官方源，电信网通用户使用)：

deb http://archive.ubuntu.com/ubuntu/ karmic main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ karmic-security main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ karmic-updates main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ karmic-proposed main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ karmic-backports main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ karmic main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ karmic-security main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ karmic-updates main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ karmic-proposed main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ karmic-backports main restricted universe multiverse

骨头兄亲自搭建并维护这个Ubuntu源（该源位于浙江杭州百兆共享宽带的电信机房)：

deb http://ubuntu.srt.cn/ubuntu/ karmic main restricted universe multiverse
deb http://ubuntu.srt.cn/ubuntu/ karmic-security main restricted universe multiverse
deb http://ubuntu.srt.cn/ubuntu/ karmic-updates main restricted universe multiverse
deb http://ubuntu.srt.cn/ubuntu/ karmic-proposed main restricted universe multiverse
deb http://ubuntu.srt.cn/ubuntu/ karmic-backports main restricted universe multiverse
deb-src http://ubuntu.srt.cn/ubuntu/ karmic main restricted universe multiverse
deb-src http://ubuntu.srt.cn/ubuntu/ karmic-security main restricted universe multiverse
deb-src http://ubuntu.srt.cn/ubuntu/ karmic-updates main restricted universe multiverse
deb-src http://ubuntu.srt.cn/ubuntu/ karmic-proposed main restricted universe multiverse
deb-src http://ubuntu.srt.cn/ubuntu/ karmic-backports main restricted universe multiverse
deb http://mirror.lupaworld.com/ubuntu/ubuntu-cn karmic main restricted universe multiverse

网易163更新服务器：

deb http://mirrors.163.com/ubuntu/ karmic main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ karmic-security main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ karmic-updates main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ karmic-proposed main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ karmic-backports main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ karmic main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ karmic-security main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ karmic-updates main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ karmic-proposed main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ karmic-backports main restricted universe multiverse 

sohu 更新服务器：

deb http://mirrors.sohu.com/ubuntu/ karmic main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ karmic-security main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ karmic-updates main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ karmic-proposed main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ karmic-backports main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ karmic main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ karmic-security main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ karmic-updates main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ karmic-proposed main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ karmic-backports main restricted universe multiverse 

Mirrors.shlug.org更新服务器（电信服务器，Ubuntu China Official Mirror, maintained by Shanghai Linux User Group）：

deb http://cn.archive.ubuntu.com/ubuntu karmic main restricted universe multiverse
deb http://cn.archive.ubuntu.com/ubuntu karmic-security main restricted universe multiverse
deb http://cn.archive.ubuntu.com/ubuntu karmic-updates main restricted universe multiverse
deb http://cn.archive.ubuntu.com/ubuntu karmic-backports main restricted universe multiverse
deb http://cn.archive.ubuntu.com/ubuntu karmic-proposed main restricted universe multiverse
deb-src http://cn.archive.ubuntu.com/ubuntu karmic main restricted universe multiverse
deb-src http://cn.archive.ubuntu.com/ubuntu karmic-security main restricted universe multiverse
deb-src http://cn.archive.ubuntu.com/ubuntu karmic-updates main restricted universe multiverse
deb-src http://cn.archive.ubuntu.com/ubuntu karmic-backports main restricted universe multiverse
deb-src http://cn.archive.ubuntu.com/ubuntu karmic-proposed main restricted universe multiverse

Mirror.lupaworld.com更新服务器（浙江省杭州市双线服务器）：

deb http://mirror.lupaworld.com/ubuntu karmic main restricted universe multiverse
deb http://mirror.lupaworld.com/ubuntu karmic-security main restricted universe multiverse
deb http://mirror.lupaworld.com/ubuntu karmic-updates main restricted universe multiverse
deb http://mirror.lupaworld.com/ubuntu karmic-backports main restricted universe multiverse
deb http://mirror.lupaworld.com/ubuntu karmic-proposed main restricted universe multiverse
deb-src http://mirror.lupaworld.com/ubuntu karmic main restricted universe multiverse
deb-src http://mirror.lupaworld.com/ubuntu karmic-security main restricted universe multiverse
deb-src http://mirror.lupaworld.com/ubuntu karmic-updates main restricted universe multiverse
deb-src http://mirror.lupaworld.com/ubuntu karmic-backports main restricted universe multiverse
deb-src http://mirror.lupaworld.com/ubuntu karmic-proposed main restricted universe multiverse

厦门大学更新服务器（教育网服务器）：

deb ftp://ubuntu.realss.cn/ubuntu/ karmic main restricted universe multiverse
deb ftp://ubuntu.realss.cn/ubuntu/ karmic-backports restricted universe multiverse
deb ftp://ubuntu.realss.cn/ubuntu/ karmic-proposed main restricted universe multiverse
deb ftp://ubuntu.realss.cn/ubuntu/ karmic-security main restricted universe multiverse
deb ftp://ubuntu.realss.cn/ubuntu/ karmic-updates main restricted universe multiverse
deb-src ftp://ubuntu.realss.cn/ubuntu/ karmic main restricted universe multiverse
deb-src ftp://ubuntu.realss.cn/ubuntu/ karmic-backports main restricted universe multiverse
deb-src ftp://ubuntu.realss.cn/ubuntu/ karmic-proposed main restricted universe multiverse
deb-src ftp://ubuntu.realss.cn/ubuntu/ karmic-security main restricted universe multiverse
deb-src ftp://ubuntu.realss.cn/ubuntu/ karmic-updates main restricted universe multiverse

成都市 电子科技大学更新服务器（教育网，推荐校园网和网通用户使用）：

deb http://ubuntu.uestc.edu.cn/ubuntu/ karmic main multiverse restricted universe
deb http://ubuntu.uestc.edu.cn/ubuntu/ karmic-backports main multiverse restricted universe
deb http://ubuntu.uestc.edu.cn/ubuntu/ karmic-proposed main multiverse restricted universe
deb http://ubuntu.uestc.edu.cn/ubuntu/ karmic-security main multiverse restricted universe
deb http://ubuntu.uestc.edu.cn/ubuntu/ karmic-updates main multiverse restricted universe
deb-src http://ubuntu.uestc.edu.cn/ubuntu/ karmic main multiverse restricted universe
deb-src http://ubuntu.uestc.edu.cn/ubuntu/ karmic-backports main multiverse restricted universe
deb-src http://ubuntu.uestc.edu.cn/ubuntu/ karmic-proposed main multiverse restricted universe
deb-src http://ubuntu.uestc.edu.cn/ubuntu/ karmic-security main multiverse restricted universe
deb-src http://ubuntu.uestc.edu.cn/ubuntu/ karmic-updates main multiverse restricted universe

== 如果无法解析uestc.edu.cn域名，请使用以下地址 ==

deb http://ubuntu.dormforce.net/ubuntu/ karmic main multiverse restricted universe
deb http://ubuntu.dormforce.net/ubuntu/ karmic-backports main multiverse restricted universe
deb http://ubuntu.dormforce.net/ubuntu/ karmic-proposed main multiverse restricted universe
deb http://ubuntu.dormforce.net/ubuntu/ karmic-security main multiverse restricted universe
deb http://ubuntu.dormforce.net/ubuntu/ karmic-updates main multiverse restricted universe
deb-src http://ubuntu.dormforce.net/ubuntu/ karmic main multiverse restricted universe
deb-src http://ubuntu.dormforce.net/ubuntu/ karmic-backports main multiverse restricted universe
deb-src http://ubuntu.dormforce.net/ubuntu/ karmic-proposed main multiverse restricted universe
deb-src http://ubuntu.dormforce.net/ubuntu/ karmic-security main multiverse restricted universe
deb-src http://ubuntu.dormforce.net/ubuntu/ karmic-updates main multiverse restricted universe

上海市上海交通大学更新服务器：

deb http://ftp.sjtu.edu.cn/ubuntu/ karmic main multiverse restricted universe
deb http://ftp.sjtu.edu.cn/ubuntu/ karmic-backports main multiverse restricted universe
deb http://ftp.sjtu.edu.cn/ubuntu/ karmic-proposed main multiverse restricted universe
deb http://ftp.sjtu.edu.cn/ubuntu/ karmic-security main multiverse restricted universe
deb http://ftp.sjtu.edu.cn/ubuntu/ karmic-updates main multiverse restricted universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ karmic main multiverse restricted universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ karmic-backports main multiverse restricted universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ karmic-proposed main multiverse restricted universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ karmic-security main multiverse restricted universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ karmic-updates main multiverse restricted universe

中国科学技术大学更新服务器：

deb http://debian.ustc.edu.cn/ubuntu/ karmic main multiverse restricted universe
deb http://debian.ustc.edu.cn/ubuntu/ karmic-backports main multiverse restricted universe
deb http://debian.ustc.edu.cn/ubuntu/ karmic-proposed main multiverse restricted universe
deb http://debian.ustc.edu.cn/ubuntu/ karmic-security main multiverse restricted universe
deb http://debian.ustc.edu.cn/ubuntu/ karmic-updates main multiverse restricted universe
deb-src http://debian.ustc.edu.cn/ubuntu/ karmic main multiverse restricted universe
deb-src http://debian.ustc.edu.cn/ubuntu/ karmic-backports main multiverse restricted universe
deb-src http://debian.ustc.edu.cn/ubuntu/ karmic-proposed main multiverse restricted universe
deb-src http://debian.ustc.edu.cn/ubuntu/ karmic-security main multiverse restricted universe
deb-src http://debian.ustc.edu.cn/ubuntu/ karmic-updates main multiverse restricted universe

中国地质大学（北京）更新服务器：

deb http://www.tofree.org/ubuntu/ karmic main restricted universe multiverse
deb http://www.tofree.org/ubuntu/ karmic-security main restricted universe multiverse
deb http://www.tofree.org/ubuntu/ karmic-updates main restricted universe multiverse
deb http://www.tofree.org/ubuntu/ karmic-proposed main restricted universe multiverse
deb http://www.tofree.org/ubuntu/ karmic-backports main restricted universe multiverse
deb-src http://www.tofree.org/ubuntu/ karmic main restricted universe multiverse
deb-src http://www.tofree.org/ubuntu/ karmic-security main restricted universe multiverse
deb-src http://www.tofree.org/ubuntu/ karmic-updates main restricted universe multiverse
deb-src http://www.tofree.org/ubuntu/ karmic-proposed main restricted universe multiverse
deb-src http://www.tofree.org/ubuntu/ karmic-backports main restricted universe multiverse 

中国台湾 台湾大学更新服务器（推荐网通用户使用，电信PING平均响应速度41MS。强烈推荐此源，比较完整，较少出现同步问题）：

deb http://ubuntu.csie.ntu.edu.tw/ubuntu/ karmic main restricted universe multiverse
deb-src http://ubuntu.csie.ntu.edu.tw/ubuntu/ karmic main restricted universe multiverse
deb http://ubuntu.csie.ntu.edu.tw/ubuntu/ karmic-updates main restricted universe multiverse
deb-src http://ubuntu.csie.ntu.edu.tw/ubuntu/ karmic-updates main restricted universe multiverse
deb http://ubuntu.csie.ntu.edu.tw/ubuntu/ karmic-backports main restricted universe multiverse
deb-src http://ubuntu.csie.ntu.edu.tw/ubuntu/ karmic-backports main restricted universe multiverse
deb http://ubuntu.csie.ntu.edu.tw/ubuntu/ karmic-security main restricted universe multiverse
deb-src http://ubuntu.csie.ntu.edu.tw/ubuntu/ karmic-security main restricted universe multiverse
deb http://ubuntu.csie.ntu.edu.tw/ubuntu/ karmic-proposed main multiverse restricted universe
deb-src http://ubuntu.csie.ntu.edu.tw/ubuntu/ karmic-proposed main restricted universe multiverse

mirror.rootguide.org更新服务器（上海市 电信）：

deb http://mirror.rootguide.org/ubuntu/ karmic main restricted universe multiverse
deb-src http://mirror.rootguide.org/ubuntu/ karmic main restricted universe multiverse
deb http://mirror.rootguide.org/ubuntu/ karmic-updates main restricted universe multiverse
deb-src http://mirror.rootguide.org/ubuntu/ karmic-updates main restricted universe multiverse
deb http://mirror.rootguide.org/ubuntu/ karmic-backports main restricted universe multiverse
deb-src http://mirror.rootguide.org/ubuntu/ karmic-backports main restricted universe multiverse
deb http://mirror.rootguide.org/ubuntu/ karmic-security main restricted universe multiverse
deb-src http://mirror.rootguide.org/ubuntu/ karmic-security main restricted universe multiverse
deb http://mirror.rootguide.org/ubuntu/ karmic-proposed main multiverse restricted universe
deb-src http://mirror.rootguide.org/ubuntu/ karmic-proposed main restricted universe multiverse

台湾的官方源速度也相当不错，有时甚至快于内地的：

deb http://tw.archive.ubuntu.com/ubuntu karmic main restricted universe multiverse
deb http://tw.archive.ubuntu.com/ubuntu karmic-security main restricted universe multiverse
deb http://tw.archive.ubuntu.com/ubuntu karmic-updates main restricted universe multiverse
deb http://tw.archive.ubuntu.com/ubuntu karmic-backports main restricted universe multiverse
deb http://tw.archive.ubuntu.com/ubuntu karmic-proposed main restricted universe multiverse
deb-src http://tw.archive.ubuntu.com/ubuntu karmic main restricted universe multiverse
deb-src http://tw.archive.ubuntu.com/ubuntu karmic-security main restricted universe multiverse
deb-src http://tw.archive.ubuntu.com/ubuntu karmic-updates main restricted universe multiverse
deb-src http://tw.archive.ubuntu.com/ubuntu karmic-backports main restricted universe multiverse
deb-src http://tw.archive.ubuntu.com/ubuntu karmic-proposed main restricted universe multiverse

以下源支持IPV6,推荐可以使用IPV6的教育网用户使用，速度在200kb/s左右，如需源代码，将deb替换成deb-src即可

deb http://mirror.switch.ch/ftp/ubuntu/ karmic main multiverse restricted universe
deb http://mirror.switch.ch/ftp/ubuntu/ karmic-backports main multiverse restricted universe
deb http://mirror.switch.ch/ftp/ubuntu/ karmic-proposed main multiverse restricted universe
deb http://mirror.switch.ch/ftp/ubuntu/ karmic-security main multiverse restricted universe
deb http://mirror.switch.ch/ftp/ubuntu/ karmic-updates main multiverse restricted universe

deb http://ftp.heanet.ie/mirrors/ubuntu/ karmic main multiverse restricted universe
deb http://ftp.heanet.ie/mirrors/ubuntu/ karmic-backports main multiverse restricted universe
deb http://ftp.heanet.ie/mirrors/ubuntu/ karmic-proposed main multiverse restricted universe
deb http://ftp.heanet.ie/mirrors/ubuntu/ karmic-security main multiverse restricted universe
deb http://ftp.heanet.ie/mirrors/ubuntu/ karmic-updates main multiverse restricted universe

deb http://ftp.kddlabs.co.jp/020/Linux/packages/ubuntu/archive/ karmic main multiverse restricted universe
deb http://ftp.kddlabs.co.jp/020/Linux/packages/ubuntu/archive/ karmic-backports main multiverse restricted universe
deb http://ftp.kddlabs.co.jp/020/Linux/packages/ubuntu/archive/ karmic-proposed main multiverse restricted universe
deb http://ftp.kddlabs.co.jp/020/Linux/packages/ubuntu/archive/ karmic-security main multiverse restricted universe
deb http://ftp.kddlabs.co.jp/020/Linux/packages/ubuntu/archive/ karmic-updates main multiverse restricted universe