libesmtp exists in RHEL6 so it should no longer be in EPEL. And the EPEL version is newer, so current behavior would be to override the package in base.
# yum list libesmtp Loaded plugins: refresh-packagekit, rhnplugin, security Available Packages libesmtp.i686 1.0.4-16.el6 epel libesmtp.x86_64 1.0.4-16.el6 epel # yum --disablerepo=epel list libesmtp Loaded plugins: refresh-packagekit, rhnplugin, security Available Packages libesmtp.i686 1.0.4-15.el6 rhel-x86_64-workstation-6 libesmtp.x86_64 1.0.4-15.el6 rhel-x86_64-workstation-6 Yes, please remove these from EPEL although after all these months I'm not sure this going to accomplish getting it done.
dead.packaged and blocked from epel6