In Centos 7 tftpd will not work with selinux. Clients will not be able to connect and this is all you'll see in the log (then nothing more):
Sep 18 14:39:15 localhost xinetd: START: tftp pid=4331 from=192.168.1.65
On the client/computer side you will see this:
PXE-M0F: Exiting Intel Boot Agent
Basically the client is being instantly connected and blocked by selinux.
1.) disable selinux in /etc/selinux/config
2.) to instantly (but temporarily disable) type