我们安装完成CentOS系统，默认都是系统自带的yum源，国内用户用yum安装软件的时候，是比较慢的，为了提高效率，一般我们会配置国内的yum源。

国内比较好的yum源有网易yum源、搜狐yum源等，现在介绍下怎么配置网易163yum源：

官方链接【CentOS镜像使用帮助】：http://mirrors.163.com/.help/centos.html

收录架构为：i386，x86_64，SRPMS

收录版本为：5.x和6.x系列

更新时间：每5小时更新一次

1、首先备份/etc/yum.repos.d/CentOS-Base.repo

mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.$(date+%F)_backup

2、根据CentOS不同版本选择下载对应的repo文件，放到/etc/yum.repos.d/ 目录

cd /etc/yum.repos.d/

# CentOS 5.x

wget http://mirrors.163.com/.help/CentOS5-Base-163.repo

# CentOS 6.x

wget http://mirrors.163.com/.help/CentOS6-Base-163.repo

3、最后，执行yum makecache生成缓存

yum makecache

OK,简单3步操作即可配置完成。
中科大yum源
[base]
name=CentOS-$releasever - Base
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os
baseurl=http://centos.ustc.edu.cn/centos/$releasever/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6

#released updates
[updates]
name=CentOS-$releasever - Updates
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates
baseurl=http://centos.ustc.edu.cn/centos/$releasever/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6

#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras
baseurl=http://centos.ustc.edu.cn/centos/$releasever/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6

#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus
baseurl=http://centos.ustc.edu.cn/centos/$releasever/centosplus/$basearch/
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6

#contrib - packages by Centos Users
[contrib]
name=CentOS-$releasever - Contrib
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=contrib
baseurl=http://centos.ustc.edu.cn/centos/$releasever/contrib/$basearch/
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6

本地yum源

[yum]
name=yum
baseurl=file:///mnt/
enabled=1 开启本地镜像
gpgcheck=0
yum源配置

vi /etc/rc.local 开机自起
mount /dev/cdrom /mnt

service iptables stop 临时关闭防火墙
chkconfig iptables off 永久关闭防火墙

vi /etc/selinux/config修改/etc/selinux/config 文件中为SELINUX="disabled" ，然后重启。如果不想重启系统，使用命令setenforce 0