Ubuntu 软件源更新(校园网)以及问题总结
最近在折腾Linux，在校园网下怎么能够很好的获取软件很是让我头疼啊~~~
总结一下吧!!!
首先是校园网的源地址：
清华大学：
https://mirrors.tuna.tsinghua.edu.cn/ 自动选择
https://mirrors6.tuna.tsinghua.edu.cn/ 只解析 IPv6
https://mirrors4.tuna.tsinghua.edu.cn/ 只解析 IPv4
进入后选择镜像名称旁边的问号，选择对应版本的源，但是一定记住只有ipv6网络的一定将mirrors修改成mirrors6
先测试一下，地址https://mirrors6.tuna.tsinghua.edu.cn/能不能打开，如果能的话，并且你的Ubuntu版本是16.04，就直接用下面的地址覆盖sources.list的内容吧。
deb http://mirrors6.tuna.tsinghua.edu.cn/ubuntu/ xenial main multiverse restricted universe
deb http://mirrors6.tuna.tsinghua.edu.cn/ubuntu/ xenial-backports main multiverse restricted universe
deb http://mirrors6.tuna.tsinghua.edu.cn/ubuntu/ xenial-proposed main multiverse restricted universe
deb http://mirrors6.tuna.tsinghua.edu.cn/ubuntu/ xenial-security main multiverse restricted universe
deb http://mirrors6.tuna.tsinghua.edu.cn/ubuntu/ xenial-updates main multiverse restricted universe
deb-src http://mirrors6.tuna.tsinghua.edu.cn/ubuntu/ xenial main multiverse restricted universe
deb-src http://mirrors6.tuna.tsinghua.edu.cn/ubuntu/ xenial-backports main multiverse restricted universe
deb-src http://mirrors6.tuna.tsinghua.edu.cn/ubuntu/ xenial-proposed main multiverse restricted universe
deb-src http://mirrors6.tuna.tsinghua.edu.cn/ubuntu/ xenial-security main multiverse restricted universe
deb-src http://mirrors6.tuna.tsinghua.edu.cn/ubuntu/ xenial-updates main multiverse restricted universe
中科大USTC镜像源
在这里配置相关参数获取，可以选择版本和网络线路
https://mirrors.ustc.edu.cn/repogen/
deb https://ipv6.mirrors.ustc.edu.cn/ubuntu/ xenial main restricted universe multiverse
deb-src https://ipv6.mirrors.ustc.edu.cn/ubuntu/ xenial main restricted universe multiverse
deb https://ipv6.mirrors.ustc.edu.cn/ubuntu/ xenial-security main restricted universe multiverse
deb-src https://ipv6.mirrors.ustc.edu.cn/ubuntu/ xenial-security main restricted universe multiverse
deb https://ipv6.mirrors.ustc.edu.cn/ubuntu/ xenial-updates main restricted universe multiverse
deb-src https://ipv6.mirrors.ustc.edu.cn/ubuntu/ xenial-updates main restricted universe multiverse
deb https://ipv6.mirrors.ustc.edu.cn/ubuntu/ xenial-backports main restricted universe multiverse
deb-src https://ipv6.mirrors.ustc.edu.cn/ubuntu/ xenial-backports main restricted universe multiverse
## Not recommended
# deb https://ipv6.mirrors.ustc.edu.cn/ubuntu/ xenial-proposed main restricted universe multiverse
# deb-src https://ipv6.mirrors.ustc.edu.cn/ubuntu/ xenial-proposed main restricted universe multiverse
北京交通大学
http://mirror.bjtu.edu.cn/cn/
另外的具体配置参考这里：
http://blog.csdn.net/bleachswh/article/details/51423585
正常的ipv4网络以后用到再总结吧：
问题总结：
1、如果在安装软件时经常出现：
比如安装python-dev时出现依赖包错误：
The following packages have unmet dependencies:
python-dev : Depends: python2.7-dev (>= 2.7.3) but it is not going to be installed
E: Unable to correct problems, you have held broken packages.
那么很大的可能是你的软件源配置出了问题，版本不对应等等。
2、