"No DHCP or ProxyDHCP offers recieved"

Can anyone suggest anything? We have 500 odd dells here, all T3400/T3500s. All PXE using MDT 2010 to image on server 2k8r2.

All bar 3 PCs are fine..they boot, they load the matrix point driver for the SAS disks, thehy get to the Broadcom UNDI screen, and..they stop. The others immediately get the "DHCP:.../" spinner, and then ask for f12 if you want to image, followed by kicking into Win7.

These 3 just sit. They don't get the "DHCP.../" for a good 5 minutes, they just sit at "Broadcom UNDI" etc. Then when they do proceed to looking for DHCP, they come up after 30-40 seconds with "PXE-e51: No DHCP or ProxyHCP offers were recieved", and kick into Win7 as usual.

Once in Win7, everything LAN wise is bang on, perfectly happy.

Now, I've flashed to BIOS A16 from A10 (thought it was a red herring, the others are all A10). I've swapped 3 cables/lan sockets from trouble free units of the same type to one of the PITA units, no change..all other units are happy, this one not. Into BIOS, flatten it to defaults, total reset, no joy.

It HAS worked fine, they all have, as they've all been imaged last summer with the Win7 build! Just all of a sudden, these 3 decide enough is enough.

They're all encased, so can't be tampered with except by us, and we haven't. LAN ports and cables also. Switches haven't changed at all since they were installed, and besides, other workstations in the socket, with the same cable are fine.

I'm really leaning towards a damaged bit of hardware..but 3 at once? Don't get me wrong, these Dells aren't the most flawless of machines..but...1 has been in place 3 years, bordering on 4..one is coming up for 18 months, and the 3rd had a new motherboard fitted not 6 months ago, for refusing to connect to the LAN come hell or high water, and upon replacement, worked perfectly until now.

Any thoughts? I'm at a bit of a loss...

Isnt there a LAN enabley-type setting somewhere in the BIOS in order to get this to work? Have they somehow lost it? Sorry, not at work so cannot check what I am waffling on about :)

Any chance that these 3 sit on a seperate subnet/VLAN ? Could they need the PXE option in DHCP server enabling if so? Long shot I know

Firmware upgrade on the switches??

Long time ago we had a similar problem, it drove me mad for days! All it was we bough a brother printer that was generating spikes of broadcast storm on the POE switches, could you believe it? Nothing was directly connected to the switches and computer where we had the DCHP problem, yet on a network (as you all well know) everything is connected to evething.

On my case a firmware upgrade to the POEs fixed the issues, good luck!

Just use the lightouch.iso in the deploy share to burn a boot CD that takes the place of the pxe boot on those ones. Had this before and the time taken to track down dodgey cables, messed STP settings or broadcast throtteling errors was way longer than just doing those few with a boot CD to kick into the MDT share.

check that there in the same subnet what ever subnet they should be when started that is. check the switch for any rouge vlans that they may be connected into for some odd reason. if they still dont play monitor what trafic there sending to the switch wire shark or capsa cola soft, might give u an insite on the dhcp requests and weather or not its the switch, server or desktop.
check your DHCP server to see if any mac's are denied an IP address or something daft.
its possible you have damaged hardware somewhere. could be the PXE chip or the network card, or possibly further up like the ports on the switch, if its beginning to go a bit wonky.

but i would try to see the DHCP communication from one of these if you can it would help give you a vague idea whats up.

I have to admit to leaning more towards hardware issues with the systems...given that if I pull the LAN cable and boot it, it still sits at this point...whereas any other will chuck up a media failure. Kind of rules the LAN out of it, sigh. That's 3 calls to Dell then, to explain and spend god knows how long on the phone. Joy.

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Originally Posted by Sirbendy

I have to admit to leaning more towards hardware issues with the systems...given that if I pull the LAN cable and boot it, it still sits at this point...whereas any other will chuck up a media failure. Kind of rules the LAN out of it, sigh. That's 3 calls to Dell then, to explain and spend god knows how long on the phone. Joy.

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Have you tried unplugging and fully draining the units with the power button beforehand. Some inband management tech and modern cards can choke out with rubbish in it's buffer which may be messing with it. Worth a try before trying to educate Dell support about what a network card is let alone the use and failure of PXE.

Is STP enabled on the switch? If it's on try disabling it (unless you need it).