[CentOS] yum install foobar, silently ignore the unknown foobar package -> Nothing to do

# yum install foobar
Loading "installonlyn" plugin
Setting up Install Process
Setting up repositories
Reading repository metadata in from local files
Parsing package install arguments
Nothing to do

Here is the output of my centos 4

# yum install foobar
Setting up Install Process
Setting up repositories
Reading repository metadata in from local files
Parsing package install arguments
No Match for argument: foobar    <<<<<<<<<<<<<<<<< This is missing in centos5
Nothing to do


any idea

-- 
Alain Spineux
aspineux gmail com
May the sources be with you