Update #1 2013-03-07
This issue seems to have been recognized by others as well.
A bug report seems to have been sent (“We added some bugreport #192750. Should be fixed next patch.”) as of february 26th 2013.
Update #2 2013-03-19
A new version of FortiOS is now released: 5.0.2 build 0179.
I’ve upgraded a Fortigate 80C to verify that the issue I’ve described below is fixed – and it is.
Just did an upgrade from FortiOS 4 to 5, which seems to contain some new code for the DHCP server (?).
I talked to someone at the support at Fortinet, that said that I had taken an unsupported upgrade path – from a too low version-4.
The issue I had was, that when booting a Lenovo laptop, using PXE on the same subnet as our WDS server, I got the following error:
PXE-E55: ProxyDHCP service did not reply to request on port 4011
I tried to mirror that switch port and look through all the traffic, but found nothing interesting.
Anyway, to confirm the issue, I formatted a Fortigate 80C with the latest build of version 4.
I did not change any settings at all on the first boot. I plugged in the WDS server (static IP) and the same Lenovo laptop, which got a dhcp lease. It found, and successfully booted from the WDS server.
I upgraded the 80C to the latest build of version 5.
Comments are appreciated!