TFTP Error - Access Violation

[T81]

Hi everyone.
I have netboot.xyz in a docker container running on Qnap.
My DHCP is on a pihole, in an LXC container on Qnap, too.
dnsmasq has been set up according linuxserver/netbootxyz:

dhcp-match=set:bios,60,PXEClient:Arch:00000
dhcp-boot=tag:bios,netboot.xyz.kpxe,,YOURSERVERIP
dhcp-match=set:efi32,60,PXEClient:Arch:00002
dhcp-boot=tag:efi32,netboot.xyz.efi,,YOURSERVERIP
dhcp-match=set:efi32-1,60,PXEClient:Arch:00006
dhcp-boot=tag:efi32-1,netboot.xyz.efi,,YOURSERVERIP
dhcp-match=set:efi64,60,PXEClient:Arch:00007
dhcp-boot=tag:efi64,netboot.xyz.efi,,YOURSERVERIP
dhcp-match=set:efi64-1,60,PXEClient:Arch:00008
dhcp-boot=tag:efi64-1,netboot.xyz.efi,,YOURSERVERIP
dhcp-match=set:efi64-2,60,PXEClient:Arch:00009
dhcp-boot=tag:efi64-2,netboot.xyz.efi,,YOURSERVERIP

YOURSERVERIP is the IP of Qnap, where the netboot.xyz container resides.
When I try to network boot a machine, the DHCP assigns an IP as supposed to, but then I get the following:

TFTP
PXE-T02: File must have global read permissions
PXE-E3C: TFTP Error - Access Violation PXE-M0F: Exiting PXE ROM.

Any suggestions on resolving this issue?

[T81]

Solved it with the help of the discord community.

The messages I was getting were coming from this part of the code:

https://git.kernel.org/pub/scm/network/tftp/tftp-hpa.git/tree/tftpd/tftpd.c#n1507

I was suggested that I should change the permission of the /config directory and the files, from in inside the container, to 777 and 666 respectively. This suggestion came from the comment at the top of that validate_access functions.

Indeed the global read permission vanished but then I started getting:

PXE-T00: Permission denied
PXE-E36: Error received from TFTP server
PXE-M0F: Exiting PXE ROM.
It seemes that chmod 775 -R /config did the job and finally it worked.

Ref: TFTP Permission denied - TFTP - openmediavault

I also noticed that any changes in files like e.g boot.cfg rendered permission errors during network booting.
I had to chmod 775 -R path-to/config on the host too in order to solve this.
I do not know if this is a Qnap specific issue or something in my configuration in general.

Special thanks to banadushi and antonym. Thanks guys.

https://discourse.linuxserver.io/t/netbootxyz-global-read-permissions-error/3108/6