Solved Cannot boot machines using "External" DHCP Server Mode

[Geppo Smart]

I'm trying to integrate iVentoy (version 1.0.19 Linux 64-bit) into my existing LAN which has isc-dhcp-server on Ubuntu serving IP addresses.
I've installed iVentoy onto this same machine and set DHCP server mode to "External".

When I try to boot machines, I get pxelinux.0 errors like this:-



If i temporarily disable isc-dhcp-server and set iVentoy to "Internal", the machines will then startup and show the list of ISO's to load.

Is something extra required when using "External" mode, there doesn't seem to be any mention in the Getting Started instructions

Looking at the screenshot, I think you forgot to change the boot file name. Please, read carefully:

• 2.1 External Mode
  

The usage scenario of external mode is that iVentoy and the third-party DHCP Server are located in the same LAN/VLAN.
In this mode, iVentoy will still start its internal DHCP server, but the internal DHCP server will only snop the DHCP packet and will not send any response. So it will not interfere with the work of the external DHCP Server.
By snopping the DHCP packet, iVentoy will record the client's BIOS mode, when the client request bootfile through TFTP, iVentoy will send it the right bootfile.
So in this mode, the DHCP server does not need to care about the client's BIOS mode. It only provides a common bootfile name (for example iventoy_loader_16000)
The bootfile name is actually a virtual file name. iVentoy will provide the real bootfile to the client according to its BIOS mode.