As i said before, Uncle Frank put me on the good way (DHCP issue). I tried before many options on the switch, and no one worked. My method for this was really empiric : many tests, many failed tests and - at least with DHCP relay - i succeed. It’s strange that a DHCP relay is necessary : all pc’s are on the same subnet. I don’t uderstand why, and i’m a little bit annoyed about this but it works for now. I made a upload/download with success. I hope that this DHCP relay won’t generate some issues on the network !

Hi, thanks for the answer. You put me on the right way. I think it works now - i can boot and perform host registration. I set up on the switch a DHCP relay. It seems ok. It was - i hope - a “simple” issue with forwarding DHCP options as you said.
Thanks again for the help.

Hi, i meet an issue with my new switch HP A5120-EI (presumed guilty)
I can’t boot : it says [B]“Could not start download: Operation not supported ([url]http://ipxe.org/3c092003[/url])”. [/B]On our network, we have HP Procurve 2425 switches and it works very well - all is working fine (unicast, multicast) but not with these A5120. I tried another one (we have 2 - maybe the first one was buggy), same issue (with the default configuration). Something must be configured, but what ?
(Ubuntu Server 12.04, FOG v. 1.2.0. Bonded NICs. undionly.kpxe in use (works fine). DHCP Windows 2012 Server.)
Help needed! Thanks!
[B][/B]