wget http://packages.sw.be/rpmforge-release/ … f.i386.rpm
http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.1-1.el5.rf.i386.rpm
rpm -ivh rpmforge-release-0.5.1-1.el5.rf.i386.rpm
yum install rrdtool rrdtool-devel -y
http://forums.cacti.net/viewtopic.php?f=6&t=46027&sid=40185ed5db0c10c663c6d43c5677db9c