Sometimes you will run into a scenario where you need to keep an OS at certain version due to vendor support. Such as EMC/IBM SAN powerpath etc.. You might also want to remain at a certain version due to change management policies.
In this example I like to use yum to keep my RHEL guest current with security and bug fixes. The problem I ran into is that Red Hat has released a new minor version of it’s Enterprise Linux 5.x, and so yum wants to update to it. Well have no fear, as there is one line you need to add to yum.conf to solve your problem.
# vi /etc/yum.conf
add this within [main]: exclude=redhat-release*
exit and save changes
Now you can run sudo yum update and you will still be at your RHEL 5.x version (issue cat /etc/redhat-release to double check)