ubuntu12.04 apt-get upgrade失敗的問題

今天，維護本身ubuntu服務器，使用apt-get upgrade更新源，可是出現下面的失敗信息：

Err http://archive.canonical.com natty InRelease   
Err http://security.ubuntu.com oneiric-security InRelease              
Err http://extras.ubuntu.com natty InRelease                           
Err http://security.ubuntu.com oneiric-security Release.gpg
  Temporary failure resolving ‘security.ubuntu.com’
Err http://archive.canonical.com natty Release.gpg
  Temporary failure resolving ‘archive.canonical.com’
Err http://extras.ubuntu.com natty Release.gpg
  Temporary failure resolving ‘extras.ubuntu.com’
Err http://gb.archive.ubuntu.com oneiric InRelease
Err http://gb.archive.ubuntu.com oneiric-updates InRelease
Err http://gb.archive.ubuntu.com natty-backports InRelease
Err http://gb.archive.ubuntu.com oneiric Release.gpg
  Temporary failure resolving ‘gb.archive.ubuntu.com’
Err http://gb.archive.ubuntu.com oneiric-updates Release.gpg
  Temporary failure resolving ‘gb.archive.ubuntu.com’
Err http://gb.archive.ubuntu.com natty-backports Release.gpg
  Temporary failure resolving ‘gb.archive.ubuntu.com’

Reading package lists... Done
W: Failed to fetch http://gb.archive.ubuntu.com/ubuntu/dists/oneiric/InRelease     
W: Failed to fetch http://gb.archive.ubuntu.com/ubuntu/dists/oneiric-updates/InRelease 
W: Failed to fetch http://gb.archive.ubuntu.com/ubuntu/dists/natty-backports/InRelease 
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/oneiric-security/InRelease 
W: Failed to fetch http://archive.canonical.com/ubuntu/dists/natty/InRelease 
W: Failed to fetch http://extras.ubuntu.com/ubuntu/dists/natty/InRelease 
W: Failed to fetch http://archive.canonical.com/ubuntu/dists/natty/Release.gpg  Temporary failure resolving ‘archive.canonical.com’
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/oneiric-security/Release.gpg  Temporary failure resolving ‘security.ubuntu.com’
W: Failed to fetch http://extras.ubuntu.com/ubuntu/dists/natty/Release.gpg  Temporary failure resolving ‘extras.ubuntu.com’
W: Failed to fetch http://gb.archive.ubuntu.com/ubuntu/dists/oneiric/Release.gpg  Temporary failure resolving ‘gb.archive.ubuntu.com’
W: Failed to fetch http://gb.archive.ubuntu.com/ubuntu/dists/oneiric-updates/Release.gpg  Temporary failure resolving ‘gb.archive.ubuntu.com’
W: Failed to fetch http://gb.archive.ubuntu.com/ubuntu/dists/natty-backports/Release.gpg  Temporary failure resolving ‘gb.archive.ubuntu.com’
W: Some index files failed to download. They have been ignored, or old ones used instead.

看了好幾個外文網站，找到了解決方案：

最近單的解決方案：

修改/etc/resolv.conf文件：

nameserver=8.8.8.8

保存，從新執行apt-get update成功！