centos 用yum安装apache是出现错误？

[root@localhost network-scripts]# yum install httpd
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=5&arch=i386&repo=os error was
[Errno 4] IOError: <urlopen error (-3, 'Temporary failure in name resolution')>
Error: Cannot find a valid baseurl for repo: base

是怎么回事？？？该怎么解决？


------解决方案--------------------
源没配置好，看看http://www.cnblogs.com/shuaixf/archive/2011/11/30/2268496.html