@george1421 Using “tcpdump” we figured out that the DISCOVER packet was getting lost on its way to the DNSMASQ service. As you stated, we could reach HTTP/HTTPS between the remote location and here, so that wasn’t the problem.

We got it working by installing a storage node, and installing DNSMASQ in a server that we located in the remote location’s switch. As my original post said, we got problems trying this solution, but after copying the “/tftpboot” folder with all the PXE binaries from our FOG server to the second server, it worked well because it succesfully reaches the boot.php file and the chainload error doesn’t appear.

Your response has been incrediby useful, thank you very much for your support.