PXE requires you add entries to /etc/services. It gets the names wrong in the documentation for the mtftp ones. It gives inetd.conf not xinetd.d/ information on setting up the server parts too. At the least I'd expect the pxe ports to be in our default /etc/services and the needed xinetd.d entries to automatically be added, even if started with disable=yes.
We are dropping support for pxe in the RHEL release and will drop it from future Red Hat Linux release. We are recommending that you use dhcp/pxelinux for X86 platforms.
Hooray !!!