[CentOS] Changing from RHEL to CentOS

[Nicolas Ross]

>I have a RHEL system and I'm thinking of changing to CentOW. How can
> this be done most easily. It is important that the e-mail setup not be
> disturbed, since it was crafted to work with an  IP that requires
> authentication.

I switch a RHEL machine in EL6 to scientific linux a while ago, and I 
suppose it's the exact same thing for Centos.

Note this applies to my x64 machine, if you're in i686, you'll just have to 
change the distrio/package name.

Here's what I did :

1. Harvest the sl-release-6.0-6.0.1.x86_64.rpm and 
redhat-logos-60.0.14-1.sl6.1.noarch.rpm from the repository.

2. Remove unneeded packages :

rpm -e rhnlib rhn-client-tools rhn-setup yum-rhn-plugin rhn-check rhnsd 
redhat-indexhtml redhat-lsb

Remove old packages and replice it with the one you downloaded :

rpm -e --nodeps redhat-release-server-6Server
rpm -hiv sl-release-6.0-6.0.1.x86_64.rpm

rpm -e --nodeps redhat-logos
rpm -hiv redhat-logos-60.0.14-1.sl6.1.noarch.rpm