As Redhat Enterprise Linux needs to be registered to use the yum source, managed to uninstalled the Redhat yum and installed the CentOS YUM source,
1, uninstall the yum source.
# rpm -aq | grep yum|xargs rpm -e --nodeps
2, install the CentOS yum and source.
# wget http://mirror.centos.org/centos/6/os/X86_64/Packages/python-iniparse-0.3.1-2.1.el6.noarch.rpm
# wget http://mirror.centos.org/centos/6/os/X86_64/Packages/yum-metadata-parser-1.1.2-14.1.el6.i686.rpm
# wget http://mirror.centos.org/centos/6/os/X86_64/Packages/yum-3.2.27-14.el6.centos.noarch.rpm
# wget http://mirror.centos.org/centos/6/os/X86_64/Packages/yum-plugin-fastestmirror-1.1.26-1.el6.noarch.rpm
# rpm -ivh python-iniparse-0.3.1-2.1.el6.noarch.rpm
# rpm -ivh yum-metadata-parser-1.1.2-14.1.el6.i686.rpm
# rpm -ivh yum-3.2.27-14.el6.centos.noarch.rpm yum-plugin-fastestmirror-1.1.26-11.el6.noarch.rpm
3, change the YUM source to mirror.nus.edu.sg
# cd /etc/yum.repos.d/
# wget http://mirrors.163.com/.help/CentOS6-Base-163.repo
# vim CentOS6-Base-163.repo
[base]
name=CentOS-$releasever - Base - nus.edu.sg
baseurl=http://mirror.nus.edu.sg/centos/6/os/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os
gpgcheck=1
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-6
#released updates
[updates]
name=CentOS-$releasever - Updates - nus.edu.sg
baseurl=http://mirror.nus.edu.sg/centos/6/updates/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates
gpgcheck=1
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-6
#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras - nus.edu.sg
baseurl=http://mirror.nus.edu.sg/centos/6/extras/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras
gpgcheck=1
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-6
#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus - nus.edu.sg
baseurl=http://mirror.nus.edu.sg/centos/6/centosplus/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus
gpgcheck=1
enabled=0
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-6
#contrib - packages by Centos Users
[contrib]
name=CentOS-$releasever - Contrib - nus.edu.sg
baseurl=http://mirror.nus.edu.sg/centos/6/contrib/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=contrib
gpgcheck=1
enabled=0
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-6
