yum安装的时候出现问题

Loaded plugins: fastestmirror,security

Setting up Install Process
Determining fastest mirrors
Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=6&arch=x86_64&repo=os&infra=stock error was
14: PYCURL ERROR 7 - "couldn't connect to host"

Error: Cannot find a valid baseurl for repo: base

ping baidu.com 能ping通

查看cd /etc/yum.repos.d/

-rw-r--r-- 1 root root 488 Jan 11 15:22 centos6.8.repo
-rw-r--r-- 1 root root 1991 May 19 2016 CentOS-Base.repo
-rw-r--r-- 1 root root 647 May 19 2016 CentOS-Debuginfo.repo
-rw-r--r-- 1 root root 289 May 19 2016 CentOS-fasttrack.repo
-rw-r--r-- 1 root root 630 May 19 2016 CentOS-Media.repo
-rw-r--r-- 1 root root 6259 May 19 2016 CentOS-Vault.repo

将Centos-* 移除，再执行yum install lrzsz 成功（lrzsz上个上传下载文件的工具）