centos 6 安装 xfce 问题

[yy001]

wget http://download.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm

[root@localhost ~]# rpm -ivh epel-release-6-8.noarch.rpm
warning: epel-release-6-8.noarch.rpm: Header V3 RSA/SHA256 Signature, key ID 0608b895: NOKEY
Preparing... ########################################### [100%]
package epel-release-6-8.noarch is already installed
[root@localhost ~]# yum grouplist
Loaded plugins: fastestmirror
Setting up Group Process
Loading mirror speeds from cached hostfile
Loading mirror speeds from cached hostfile
Error: Cannot retrieve metalink for repository: epel. Please verify its path and try again


导入这个rpm后 yum 用不了
这是咋回事，怎么恢复呢

[Patchouli]

先yum makecache 再试试yum grouplist