[CentOS] tftpd server S not responding

I have a tftpd server S running on centos 7 and managed by systemd

It is not respoding to A server which is sending the tftp read request RRQ.

I do see the RRQ packets coming from A to S, but S never responds back from
a different port Y to A

So this part is working fine


https://en.wikipedia.org/wiki/Trivial_File_Transfer_Protocol#/media/File:Tftp-rrq.svg

But I do not see any attempts to even send a data packet back in my packet
capture running on S

So this event is not occuring, as if my tftpd server is dead. I have the
firewalld turned off on S to eliminate
the possibility that firewalld blocking those packets from reeaching to
tftpd daemon. I also turned off selinux to eliminate
any permission issue.


https://en.wikipedia.org/wiki/Trivial_File_Transfer_Protocol#/media/File:Tftp-dat1-dwn.svg

I do have tftpd running and managed by systemd

$ systemctl status -l tftp
● tftp.service - Tftp Server
   Loaded: loaded (/etc/systemd/system/tftp.service; indirect; vendor
preset: disabled)
   Active: active (running) since Wed 2018-03-28 18:57:42 UTC; 1min 44s ago
     Docs: man:in.tftpd
 Main PID: 1685 (in.tftpd)
   Memory: 136.0K
   CGroup: /system.slice/tftp.service
           └─1685 /usr/sbin/in.tftpd --verbose --verbosity 10 --secure
/tftpboot --port-range 4069:4169

Mar 28 18:57:42 S.example.net systemd[1]: Started Tftp Server.
Mar 28 18:57:42 S.example.net systemd[1]: Starting Tftp Server...

Any help is appreciated!


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