If you are configuring something on RHEL/CENTOS and you can't wrap your brain about why it isn't working when you know it should. It's probably selinux. Remove selinux temporarily by doing the following:
edit /etc/sysconfig/selinux
change SELINUX=enforced to disabled
Reboot and see if it's working. If you're on a production box I would enable selinux again by changing it back to enforced.
