一、使用更新源的國內鏡像
CentOS 安裝完畢，首先應該修改更新源，並升級到最新的系統。
國內速度較快的常用更新源：
http://mirror.be10.com/centos/
http://centos.candishosting.com.cn/
http://ftp.sjtu.edu.cn/centos/
http://ftp.hostrino.com/pub/centos/
http://mirrors.ta139.com/centos/
http://ftp.iasi.roedu.net/mirrors/centos.org/centos/
http://centos.ustc.edu.cn/centos/
http://mirrors.163.com/centos/
首先備份CentOS-Base.repo，然後再編輯 yum 的配置文件
[admingu@googe ~]$ sudo cp /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.bak
[admingu@googe ~]$ sudo vi /etc/yum.repos.d/CentOS-Base.repo
| [base] name=CentOS-$releasever - Base #mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os #baseurl=http://mirror.centos.org/centos/$releasever/os/$basearch/ baseurl=http://centos.candishosting.com.cn/$releasever/os/$basearch/ http://mirrors.ta139.com/centos/$releasever/os/$basearch/ http://mirror.be10.com/centos/$releasever/os/$basearch/ http://ftp.sjtu.edu.cn/centos/$releasever/os/$basearch/ http://ftp.hostrino.com/pub/centos/$releasever/os/$basearch/ http://centos.ustc.edu.cn/centos/$releasever/os/$basearch/ http://mirrors.163.com/centos/$releasever/os/$basearch/ gpgcheck=1 gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5 #released updates [updates] name=CentOS-$releasever - Updates #mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates #baseurl=http://mirror.centos.org/centos/$releasever/updates/$basearch/ baseurl=http://centos.candishosting.com.cn/$releasever/updates/$basearch/ http://mirrors.ta139.com/centos/$releasever/updates/$basearch/ http://mirror.be10.com/centos/$releasever/updates/$basearch/ http://ftp.sjtu.edu.cn/centos/$releasever/updates/$basearch/ http://ftp.hostrino.com/pub/centos/$releasever/updates/$basearch/ http://centos.ustc.edu.cn/centos/$releasever/updates/$basearch/ http://mirrors.163.com/centos/$releasever/updates/$basearch/ gpgcheck=1 gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5 #packages used/produced in the build but not released [addons] name=CentOS-$releasever - Addons #mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=addons #baseurl=http://mirror.centos.org/centos/$releasever/addons/$basearch/ baseurl=http://centos.candishosting.com.cn/$releasever/addons/$basearch/ http://mirrors.ta139.com/centos/$releasever/addons/$basearch/ http://mirror.be10.com/centos/$releasever/addons/$basearch/ http://ftp.sjtu.edu.cn/centos/$releasever/addons/$basearch/ http://ftp.hostrino.com/pub/centos/$releasever/addons/$basearch/ http://centos.ustc.edu.cn/centos/$releasever/addons/$basearch/ http://mirrors.163.com/centos/$releasever/addons/$basearch/ gpgcheck=1 gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5 #additional packages that may be useful [extras] name=CentOS-$releasever - Extras #mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras #baseurl=http://mirror.centos.org/centos/$releasever/extras/$basearch/ baseurl=http://centos.candishosting.com.cn/$releasever/extras/$basearch/ http://mirrors.ta139.com/centos/$releasever/extras/$basearch/ http://mirror.be10.com/centos/$releasever/extras/$basearch/ http://ftp.sjtu.edu.cn/centos/$releasever/extras/$basearch/ http://ftp.hostrino.com/pub/centos/$releasever/extras/$basearch/ http://centos.ustc.edu.cn/centos/$releasever/extras/$basearch/ http://mirrors.163.com/centos/$releasever/extras/$basearch/ gpgcheck=1 gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5 #additional packages that extend functionality of existing packages [centosplus] name=CentOS-$releasever - Plus #mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus #baseurl=http://mirror.centos.org/centos/$releasever/centosplus/$basearch/ baseurl=http://centos.candishosting.com.cn/$releasever/centosplus/$basearch/ http://mirrors.ta139.com/centos/$releasever/centosplus/$basearch/ http://mirror.be10.com/centos/$releasever/centosplus/$basearch/ http://ftp.sjtu.edu.cn/centos/$releasever/centosplus/$basearch/ http://ftp.hostrino.com/pub/centos/$releasever/centosplus/$basearch/ http://centos.ustc.edu.cn/centos/5$releasever/centosplus/$basearch/ http://mirrors.163.com/centos/$releasever/centosplus/$basearch/ gpgcheck=1 enabled=0 gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5 #contrib - packages by Centos Users [contrib] name=CentOS-$releasever - Contrib #mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=contrib #baseurl=http://mirror.centos.org/centos/$releasever/contrib/$basearch/ baseurl=http://centos.candishosting.com.cn/$releasever/contrib/$basearch/ http://mirrors.ta139.com/centos/$releasever/contrib/$basearch/ http://mirror.be10.com/centos/$releasever/contrib/$basearch/ http://ftp.sjtu.edu.cn/centos/$releasever/contrib/$basearch/ http://ftp.hostrino.com/pub/centos/$releasever/contrib/$basearch/ gpgcheck=1 enabled=0 gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5 |
其中：
repositoryid:用於指定一個倉庫
name：用於指定易讀的倉庫名稱
baseurl：用於指定本倉庫的URL，可以是以下的3種類型，如http,ftp,file
mirrorlist：用於指定倉庫的鏡像站點
enable：用於指定是否使用本倉庫，默認值爲1，即可用。
gpgcheck：用於指定是否檢查軟件包的GPG簽名。
gpgkey：用於指定GPG簽名文件的URL。
執行命令：
[admingu@googe ~]$ sudo rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY*
二、使用非官方更新源
下面以安裝rpmforge和DAG軟件包爲例添加非官方更新源
I、添加rmpforge軟件庫
1）到http://dag.wieers.com/rpm/packages/rpmforge-release/查找適用於RHEL5/CentOS5的軟件包。
2）下載適用於RHEL5/CentOS5的軟件包。
[admingu@googe ~]$ sudo wget http://dag.wieers.com/rpm/packages/rpmforge-release/rpmforge-release-0.3.6-1.el5.rf.i386.rpm
[admingu@googe ~]$ sudo rpm -ivh rpmforge-release-0.3.6-1.el5.rf.i386.rpm
[admingu@googe ~]$ sudo rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-rpmforge-*
安裝rpmforge-release軟件包之後，就可以看到/etc/yum.repos.d/rpmforge.repo文件，以後yum就可以使用這個更新源了。
II、添加DAG更新倉庫 。//這個庫我更新時總是出現問題，望達人幫我一下！
1)在/etc/yum.repos.d/下建立dag.repo
2)編輯dag.repo
[admingu@googe ~]$ sudo vi /etc/yum.repos.d/dag.repo
[dag]
name=Dag RPM Repository for Red Hat Enterprise Linux
baseurl=http://apt.sw.be/redhat/el5/en/i386/dag/
gpgcheck=1
enabled=1
gpgkey=http://dag.wieers.com/rpm/packages/RPM-GPG-KEY.dag.txt
保存退出。
然後導入Key,
[admingu@googe ~]$ wget http://dag.wieers.com/rpm/packages/RPM-GPG-KEY.dag.txt
[admingu@googe ~]$ sudo rpm --import RPM-GPG-KEY.dag.txt
[admingu@googe ~]$ sudo rm -f RPM-GPG-KEY.dag.txt //這個可以先移除也可以不移除
以下是好友Nick提供的解決方法，非常感謝他！
在定義 yum 非官方庫 dag.repo 後，使用 yum 安裝非官方庫裏定義的軟件是，如果出現錯誤：
Reading repository metadata in from local files
primary.xml.gz 100% |=========================| 883 kB 00:59
http://apt.sw.be/redhat/el5/en/i386/dag/repodata/primary.xml.gz: [Errno -1] Metadata file does not match checksum
Trying other mirror.
Error: failure: repodata/primary.xml.gz from dag: [Errno 256] No more mirrors to try.
這個錯誤應該是因爲"/var/cache/yum/dag/”裏的 primary.xml.gz 不能通過校驗導致的。(暫時找不到原因,用多線程軟件下載就沒問題,如'myget')
這個錯誤我自己的解決方法是：是用軟件'myget'下載 primary.xml.gz 到 "/var/cache/yum/dag/” ；然後再重新用yum安裝軟件。
三、使用如下命令更新到最新系統
# yum upgrade
四、安裝必要的軟件工具
# yum install wget bzip2 unzip zip nmap tree lynx fileutils ncftp lftp
若您需要在本機編譯源代碼的軟件，請安裝開發工具組的軟件包
# yum groupinstall "Development Tools"