Configure the yum source of RHEL 5

Many of the RHEL we bought on the market are pirated, and there is no way to update them online, that is, not yum.
Solution:
Rpm-Qa yum
Get:
Yum-3.0.5-1.el5.
You can see that the yum software has been installed, uninstall it,
Rpm e yum-3.0.5-1.el5
Then we download a new Yum URL that we can use:
Http://ftp.nara.wide.ad.jp/pub/Linux/centos/5.1/ OS /x86_64/CentOS/yum-3.0.5-1.el5.centos.5.noarch.rpm
After the installation, set the yum Source:
Vim/etc/yum. Repos. d/CentOS-Base.repo
Add as follows:
[Base]
Name = centos-$ releasever-Base

Baseurl = http://ftp.nara.wide.ad.jp/pub/linux/centos/5.1/ OS /?basearch/
Gpgcheck = 1
# Released updates
[Update]
Name = centos-$ releasever-Updates
Baseurl = http://ftp.nara.wide.ad.jp/pub/linux/centos/5.1/updates/#basearch/
Gpgcheck = 1
# Packages used/produced in the build but not released
[Addons]
Name = centos-$ releasever-Addons
Baseurl = http://ftp.nara.wide.ad.jp/pub/linux/centos/5.1/addons/?basearch/
Gpgcheck = 1
# Additional packages that may be useful
[Extras]
Name = centos-$ releasever-extras
Baseurl = http://ftp.nara.wide.ad.jp/pub/linux/centos/5.1/extras/?basearch/
Gpgcheck = 1

Vim/etc/yum. Repos. d/Dag. Repo
Add as follows:
[Dag]
Name = Dag RPM repository for rhel5
Baseurl = http://ftp.riken.jp/linux/dag/redhat/el5/en/?basearch/dag/
Enabled = 1
Gpgcheck = 1
Gpgkey = http://ftp.riken.jp/Linux/dag/packages/RPM-GPG-KEY.dag.txt

Try again.