Yum-protectbase on Red Hat
From Consultancy.EdVoncken.NET
Since version 5, Red Hat is moving from up2date to yum for software updates.
On CentOS, the yum-protectbase plugin is very helpful to prevent third party repositories from clobbering your CentOS installation. This plugin works by adding a configuration setting to each repository in /etc/yum.repos.d/
Unfortunately, Red Hat Enterprise Linux 5 uses "yum-rhn-plugin", and there is no .repo file for the Red Hat repositories. This means that the yum-protectbase cannot protect the RHEL repositories.
Efforts are underway to work around this, for example the yum-protectrhn plugin.