vim /etc/yum.repos.d/CentOS-Base.repo

uncomment mirrorlist=*** --Internet source comment baseurl =**** --LAN source

CentOS 6

rpm -ivh http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm rpm -ivh http://mirrors.kernel.org/fedora-epel/6 _ /i386/epel-release-6-8.noarch.rpm

yum repolist 

yum update