一：问题概述
ubuntu，我们在使用apt新装软件的时候，会使用官方的网站去下载软件，但是会因为国内的转接点太多，而导致下载的速度非常慢 ，我们可以通过换成一些中间的节点来进行下载，比如阿里源，中科大源，清华源等等，这样的网站，他们会定时和官方的源进行同步和更新，而我们直接同步他们，速度就会比直接同步官方的源快很多，这样能够大大增加我们的下载软件的速度。
二：ubuntu系统更换源
更换源的方法非常简单:修改/etc/apt/sources.list文件即可
2.1：进入/etc/apt/
cd /etc/apt
2.2：修改sources.list文件
sudo vi sources.list (要有管理员权限)
2.3：可以在修改前先对 sources.list文件进行备份
sudo cp sources.list sources.list.bak
2.4:删除掉sources.list的其他内容，任意选择一种源的内容复制粘贴进去，保存，例如，选择阿里源
2.5:更新apt
sudo apt-get update
三：ubuntu各个版本的阿里云源内容
3.1：ubuntu16.04 LTS
3.1.1：阿里源：
deb-src http://archive.ubuntu.com/ubuntu xenial main restricted #Added by software-properties
deb http://mirrors.aliyun.com/ubuntu/ xenial main restricted
deb-src http://mirrors.aliyun.com/ubuntu/ xenial main restricted multiverse universe #Added by software-properties
deb http://mirrors.aliyun.com/ubuntu/ xenial-updates main restricted
deb-src http://mirrors.aliyun.com/ubuntu/ xenial-updates main restricted multiverse universe #Added by software-properties
deb http://mirrors.aliyun.com/ubuntu/ xenial universe
deb http://mirrors.aliyun.com/ubuntu/ xenial-updates universe
deb http://mirrors.aliyun.com/ubuntu/ xenial multiverse
deb http://mirrors.aliyun.com/ubuntu/ xenial-updates multiverse
deb http://mirrors.aliyun.com/ubuntu/ xenial-backports main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ xenial-backports main restricted universe multiverse #Added by software-properties
deb http://archive.canonical.com/ubuntu xenial partner
deb-src http://archive.canonical.com/ubuntu xenial partner
deb http://mirrors.aliyun.com/ubuntu/ xenial-security main restricted
deb-src http://mirrors.aliyun.com/ubuntu/ xenial-security main restricted multiverse universe #Added by software-properties
deb http://mirrors.aliyun.com/ubuntu/ xenial-security universe
deb http://mirrors.aliyun.com/ubuntu/ xenial-security multiverse
3.1.2：东北大学：
deb-src http://mirror.neu.edu.cn/ubuntu/ xenial main restricted #Added by software-properties
deb http://mirror.neu.edu.cn/ubuntu/ xenial main restricted
deb-src http://mirror.neu.edu.cn/ubuntu/ xenial restricted multiverse universe #Added by software-properties
deb http://mirror.neu.edu.cn/ubuntu/ xenial-updates main restricted
deb-src http://mirror.neu.edu.cn/ubuntu/ xenial-updates main restricted multiverse universe #Added by software-properties
deb http://mirror.neu.edu.cn/ubuntu/ xenial universe
deb http://mirror.neu.edu.cn/ubuntu/ xenial-updates universe
deb http://mirror.neu.edu.cn/ubuntu/ xenial multiverse
deb http://mirror.neu.edu.cn/ubuntu/ xenial-updates multiverse
deb http://mirror.neu.edu.cn/ubuntu/ xenial-backports main restricted universe multiverse
deb-src http://mirror.neu.edu.cn/ubuntu/ xenial-backports main restricted universe multiverse #Added by software-properties
deb http://archive.canonical.com/ubuntu xenial partner deb-src http://archive.canonical.com/ubuntu xenial partner
deb http://mirror.neu.edu.cn/ubuntu/ xenial-security main restricted
deb-src http://mirror.neu.edu.cn/ubuntu/ xenial-security main restricted multiverse universe #Added by software-properties
deb http://mirror.neu.edu.cn/ubuntu/ xenial-security universe
deb http://mirror.neu.edu.cn/ubuntu/ xenial-security multiverse
3.1.3：清华大学：
deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial main restricted
deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-updates main restricted
deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial universe
deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-updates universe
deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial multiverse
deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-updates multiverse
deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-backports main restricted universe multiverse
deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-security main restricted
deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-security universe deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-security multiverse
3.2：ubuntu 14.04 LTS
3.2.1：Ubuntu 官方更新服务器（欧洲，此为官方源，国内较慢，但无同步延迟问题，电信、移动/铁通、联通等公网用户可以使用)：
deb http://archive.ubuntu.com/ubuntu/ trusty main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ trusty-security main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ trusty-updates main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ trusty-proposed main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ trusty-backports main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ trusty main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ trusty-security main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ trusty-updates main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ trusty-proposed main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ trusty-backports main restricted universe multiverse
Ubuntu官方提供的其他软件（第三方闭源软件等）：
deb http://archive.canonical.com/ubuntu/ trusty partner
deb http://extras.ubuntu.com/ubuntu/ trusty main
3.2.2：阿里云：
deb http://mirrors.aliyun.com/ubuntu/ trusty main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ trusty-security main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ trusty-updates main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ trusty-proposed main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ trusty-backports main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ trusty main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ trusty-security main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ trusty-updates main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ trusty-proposed main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ trusty-backports main restricted universe multiverse
3.2.3：以下为有教育网接入的服务器（推荐教育网用户使用，部分非教育网用户也有可观的速度。教育网用户请优先使用IPv6地址。
中国科学技术大学更新服务器（位于合肥，千兆教育网接入，百兆电信/联通线路智能路由），由中科大Linux 用户协会和中科大学网络信息中心维护，包含其他开源镜像，Deepin 官方服务器 实际亦指向此处：
deb http://debian.ustc.edu.cn/ubuntu/ trusty main multiverse restricted universe
deb http://debian.ustc.edu.cn/ubuntu/ trusty-backports main multiverse restricted universe
deb http://debian.ustc.edu.cn/ubuntu/ trusty-proposed main multiverse restricted universe
deb http://debian.ustc.edu.cn/ubuntu/ trusty-security main multiverse restricted universe
deb http://debian.ustc.edu.cn/ubuntu/ trusty-updates main multiverse restricted universe
deb-src http://debian.ustc.edu.cn/ubuntu/ trusty main multiverse restricted universe
deb-src http://debian.ustc.edu.cn/ubuntu/ trusty-backports main multiverse restricted universe
deb-src http://debian.ustc.edu.cn/ubuntu/ trusty-proposed main multiverse restricted universe
deb-src http://debian.ustc.edu.cn/ubuntu/ trusty-security main multiverse restricted universe
deb-src http://debian.ustc.edu.cn/ubuntu/ trusty-updates main multiverse restricted universe
IPv6-Only 地址
deb http://mirrors6.ustc.edu.cn/ubuntu/ trusty main multiverse restricted universe
deb http://mirrors6.ustc.edu.cn/ubuntu/ trusty-backports main multiverse restricted universe
deb http://mirrors6.ustc.edu.cn/ubuntu/ trusty-proposed main multiverse restricted universe
deb http://mirrors6.ustc.edu.cn/ubuntu/ trusty-security main multiverse restricted universe
deb http://mirrors6.ustc.edu.cn/ubuntu/ trusty-updates main multiverse restricted universe
deb-src http://mirrors6.ustc.edu.cn/ubuntu/ trusty main multiverse restricted universe
deb-src http://mirrors6.ustc.edu.cn/ubuntu/ trusty-backports main multiverse restricted universe
deb-src http://mirrors6.ustc.edu.cn/ubuntu/ trusty-proposed main multiverse restricted universe
deb-src http://mirrors6.ustc.edu.cn/ubuntu/ trusty-security main multiverse restricted universe
deb-src http://mirrors6.ustc.edu.cn/ubuntu/ trusty-updates main multiverse restricted universe
3.2.4搜狐更新服务器（山东联通千兆接入，官方中国大陆地区镜像跳转至此） ，包含其他开源镜像：
deb http://mirrors.sohu.com/ubuntu/ trusty main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ trusty-security main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ trusty-updates main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ trusty-proposed main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ trusty-backports main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ trusty main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ trusty-security main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ trusty-updates main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ trusty-proposed main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ trusty-backports main restricted universe multiverse
3.2.5：网易163更新服务器（广东广州电信/联通千兆双线接入），包含其他开源镜像：
deb http://mirrors.163.com/ubuntu/ trusty main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ trusty-security main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ trusty-updates main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ trusty-proposed main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ trusty-backports main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ trusty main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ trusty-security main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ trusty-updates main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ trusty-proposed main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ trusty-backports main restricted universe multiverse
Ubuntu 16.04更新时卡在
0% [Connecting to cn.archive.ubuntu.com (2001:67c:1562::19)] [Connecting to security.ubuntu.com (2001:67c:1560:8001::14)]的解决办法：
这是因为默认采用了IPv6进行更新，需要修改回IPv4.
$ sudo vim /etc/gai.conf将54行的内容
precedence ::ffff:0:0/96 100去掉注释，保存退出就可以了。注意50行内容和54行很相似，不要弄混。