第一种方法:

yum源来自chinalinuxpub.com,用的是centos包,

下载地址: http://www.chinalinuxpub.com/yum.tgz

安装:

tar zxvf yum.tgz

cd yum

rpm -ivh *.rpm

rm -rf /etc/yum.repos.d/CentOS-Base.repo

vi /etc/yum.repos.d/as4-update.repo

加入：

#released updates

[update]

name=Red Hat Enterprise AS release 4 Updates

baseurl=http://ftp.chinalinuxpub.com/redhat/enterprise/updates/4AS/

gpgcheck=1

gpgkey=http://ftp.chinalinuxpub.com/redhat/enterprise/RPM-GPG-KEY-linuxpub

vi /etc/yum.repos.d/as4-base.repo

加入：

#released base

[base]

name=Red Hat Enterprise AS release 4 Updates

baseurl=http://ftp.chinalinuxpub.com/redhat/enterprise/os/i***/RedHat/

gpgcheck=1

gpgkey=http://ftp.chinalinuxpub.com/redhat/enterprise/RPM-GPG-KEY-linuxpub

然后就可以正常使用yum了.

第二种方法:利用CentOS 的yum库升级RHEL AS4

1.下载并安装yum-2.4.0-1.centos4.noarch.rpm文件，下载地址为：

ftp://ftp.pbone.net/mirror/ftp.centos.org/4.5/os/alpha/CentOS/RPMS/yum-2.4.2-1.centos4.noarch.rpm

2.修改或建立/etc/yum.repos.d/CentOS-Base.repo为如下内容：

[base]

name=CentOS-$releasever - Base

baseurl=http://ftp.riken.jp/Linux/caos/centos/4.5/os/$basearch/

gpgcheck=1

#released updates

[update]

name=CentOS-$releasever - Updates

baseurl=http://ftp.riken.jp/Linux/caos/centos/4.5/updates/$basearch/

gpgcheck=1

#packages used/produced in the build but not released

[addons]

name=CentOS-$releasever - Addons

baseurl=http://ftp.riken.jp/Linux/caos/centos/4.5/addons/$basearch/

gpgcheck=1

#additional packages that may be useful

[extras]

name=CentOS-$releasever - Extras

baseurl=http://ftp.riken.jp/Linux/caos/centos/4.5/extras/$basearch/

gpgcheck=1

3.修改或建立/etc/yum.repos.d/dag.repo为如下内容：

[dag]

name=Dag RPM Repository for RHEL4

baseurl=http://ftp.riken.jp/Linux/dag/redhat/el4/en/$basearch/dag/

enabled=1

gpgcheck=1

gpgkey=http://ftp.riken.jp/Linux/dag/packages/RPM-GPG-KEY.dag.txt

4.运行update:

yum update

5.升级：

yum upgrade

6.安装其它软件，例如：

yum install mplayer