Rationale:  Initially I had chosen “Medium” for Firewall Configuration. In the Red Hat documentation, I read that, in this case your firewall will not allow access to certain resources on your system. By default, access to these resources are not allowed-

·        Ports lower than 1023 – the standard reserved ports, used by most system services, such as FTP, SSH, telnet and HTTP  {Note: TFTP uses port 69}

·        The NFS server port (2049)

So, I finally decided to do a fresh installation choosing “No Firewall”

I am sure then your TFTP server will work as desired.

-Ranjeeta