1. You configure the PXE installation server in Redhat Enterprise Linux 5, which includes DHCP server, DNS server (Purely optional), TFTP server, NFS server and other package dependancy services (like xinetd) in one machine. Remember that you have to copy the entire DVD to the NFS location which is usually /var/ftp/pub.
2. Disable the IPtables (for newbies) or Post some specified IP Table rules which provides access for the port number 69 (tftp) (for advanced users), check in the client machine for installation.
3. Then Configure YUM server with the same /var/ftp/pub path, which has to use the same set of rpms.
4. You will get the bug, when you again use the installation server. It means that you can not use the same installation server path for YUM server.
It is the bug in RHEL5.