最近突然不能 update 了？？？哥哥们帮我

[Zandyo]

root@localhost:/etc/apache2/sites-available$ sudo apt-get update
Err http://ubuntu.cnsite.org dapper Release.gpg
Temporary failure resolving 'ubuntu.cnsite.org'
Err http://ubuntu.cnsite.org dapper-updates Release.gpg
Temporary failure resolving 'ubuntu.cnsite.org'
Err http://ubuntu.cnsite.org dapper-backports Release.gpg
Temporary failure resolving 'ubuntu.cnsite.org'
Err http://ubuntu.cnsite.org dapper-security Release.gpg
Temporary failure resolving 'ubuntu.cnsite.org'
Err http://ubuntu.cnsite.org dapper Release.gpg
Temporary failure resolving 'ubuntu.cnsite.org'
Failed to fetch http://ubuntu.cnsite.org/ubuntu/dists/d ... elease.gpg Temporary failure resolving 'ubuntu.cnsite.org'
Failed to fetch http://ubuntu.cnsite.org/ubuntu/dists/d ... elease.gpg Temporary failure resolving 'ubuntu.cnsite.org'
Failed to fetch http://ubuntu.cnsite.org/ubuntu/dists/d ... elease.gpg Temporary failure resolving 'ubuntu.cnsite.org'
Failed to fetch http://ubuntu.cnsite.org/ubuntu/dists/d ... elease.gpg Temporary failure resolving 'ubuntu.cnsite.org'
Failed to fetch http://ubuntu.cnsite.org/ubuntu-cn/dist ... elease.gpg Temporary failure resolving 'ubuntu.cnsite.org'
Reading package lists... Done
W: Some index files failed to download, they have been ignored, or old ones used instead.

我换了好几个源都是这样的，哪个大大知道怎么弄，帮我解决下，谢谢！！

我去 root@localhost:/etc/apache2/sites-available$ ping ubuntu.cnsite.org
它提示：ping: unknown host ubuntu.cnsite.org

晕掉了。ssh是可以正常连上的，apache也在跑的好好的，网页能浏览，其他的也没看出什么异常，就是不知道怎么搞的不能update，以前都好好的，

我又试了下，ping 什么站都说unknown host，晕死了，对了我服务器是托管的.

[孤笑客]

把/etc/apt/apt.conf删了试试

[Zandyo]

把/etc/apt/apt.conf删了试试

删除了之后还是没用啊，大哥们继续帮我啊

[BigSnake.NET]

DNS解釋失敗。。

[goldfox_79]

哪里的源啊，我这里能够DNS解析但是连不上，换cn99的吧

[Zandyo]

哪里的源啊，我这里能够DNS解析但是连不上，换cn99的吧

大哥，换了一样没用啊

[Zandyo]

DNS解釋失敗。。

大哥，如何解决啊？？谢谢！