مشکل در ابتدای نصب

[reza0071]

فایروال رو با دستور setup خاموش کردم
اینم دستور yum updata

[root@localhost ~]# yum update
Loaded plugins: fastestmirror, security
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
[root@localhost ~]#