更新不了源啊
wt@ubuntu14:~$ sudo apt update
[sudo] password for wt:
Err http://security.ubuntu.com trusty-security InRelease

0% [Connecting to mirrors.yun-idc.com] [Connecting to hk.arch Err http://security.ubuntu.com trusty-security Release.gpg
Could not resolve 'security.ubuntu.com'
0% [Connecting to mirrors.yun-idc.com] [Connecting to hk.arch Err http://hk.archive.ubuntu.com trusty-updates InRelease

Err http://hk.archive.ubuntu.com trusty InRelease

Err http://hk.archive.ubuntu.com trusty-backports InRelease

Err http://hk.archive.ubuntu.com trusty-updates Release.gpg
Could not resolve 'hk.archive.ubuntu.com'
Err http://hk.archive.ubuntu.com trusty Release.gpg
Could not resolve 'hk.archive.ubuntu.com'
Err http://hk.archive.ubuntu.com trusty-backports Release.gpg
Could not resolve 'hk.archive.ubuntu.com'
Err http://mirrors.yun-idc.com trusty InRelease

Err http://mirrors.yun-idc.com trusty Release.gpg
Could not resolve 'mirrors.yun-idc.com'
Reading package lists... Done
W: Failed to fetch http://mirrors.yun-idc.com/ubuntu/dists ... /InRelease

W: Failed to fetch http://hk.archive.ubuntu.com/ubuntu/dis ... /InRelease

W: Failed to fetch http://hk.archive.ubuntu.com/ubuntu/dis ... /InRelease

W: Failed to fetch http://hk.archive.ubuntu.com/ubuntu/dis ... /InRelease

W: Failed to fetch http://security.ubuntu.com/ubuntu/dists ... /InRelease

W: Failed to fetch http://security.ubuntu.com/ubuntu/dists ... elease.gpg Could not resolve 'security.ubuntu.com'

W: Failed to fetch http://hk.archive.ubuntu.com/ubuntu/dis ... elease.gpg Could not resolve 'hk.archive.ubuntu.com'

W: Failed to fetch http://hk.archive.ubuntu.com/ubuntu/dis ... elease.gpg Could not resolve 'hk.archive.ubuntu.com'

W: Failed to fetch http://hk.archive.ubuntu.com/ubuntu/dis ... elease.gpg Could not resolve 'hk.archive.ubuntu.com'

W: Failed to fetch http://mirrors.yun-idc.com/ubuntu/dists ... elease.gpg Could not resolve 'mirrors.yun-idc.com'

W: Some index files failed to download. They have been ignored, or old ones used instead

下边为源配置文件；
wt@ubuntu14:~$ sudo vim /etc/apt/sources.list



# deb cdrom:[Ubuntu-Server 14.04.4 LTS _Trusty Tahr_ - Release i386 (20160217.1)]/ trusty main restricted

#deb cdrom:[Ubuntu-Server 14.04.4 LTS _Trusty Tahr_ - Release i386 (20160217.1)]/ trusty main restricted

# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://mirrors.yun-idc.com/ubuntu/ trusty main restricted
deb-src http://mirrors.yun-idc.com/ubuntu/ trusty main restricted

## Major bug fix updates produced after the final release of the
"/etc/apt/sources.list" 62L, 3318C 1,1 Top

我换了几个 地址了 还是不起作用啊
我之前桌面版的一直用这个源的 为什么服务器上却用不了；http://mirrors.yun-idc.com/ubuntu/
这个源 我这里是最快的
以下为 14.04 服务器列表
服务器列表
可将 http://cn.archive.ubuntu.com/ubuntu/ 替换为下列任意服务器：

Ubuntu 官方（欧洲，国内较慢，无同步延迟）
http://archive.ubuntu.com/ubuntu/
Ubuntu 官方中国（目前是阿里云）
http://cn.archive.ubuntu.com/ubuntu/
网易（广东广州电信/联通千兆双线接入）
http://mirrors.163.com/ubuntu/
搜狐（山东联通千兆接入）
http://mirrors.sohu.com/ubuntu/
阿里云（北京万网/浙江杭州阿里云服务器双线接入）
http://mirrors.aliyun.com/ubuntu/
中国开源软件中心
http://mirrors.oss.org.cn/ubuntu/
首都在线科技
http://mirrors.yun-idc.com/ubuntu/
Linux Story
http://mirrors.linuxstory.org/ubuntu/
贝特康姆（江苏常州电信）
http://centos.bitcomm.cn/ubuntu

抱歉 已经找到解决方法了 已解决