United Kingdom Endpoint Management User Group

 View Only
  • 1.  PXE strange responses

    Posted Aug 26, 2010 12:49 PM
    Hi,

    DS7.1, new installation here. 6.9 is still on the same site server. All part of a new NS7 migration (which went well eventually)

    Initially during testing we got the same type of F8 prompt menu on first PXE connect that i got in 6.9. Then at some stage during configuration it stopped appearing completely. This means that the standard boot image will be sent if the conditions are true. Perhaps this wouldnt be a problem if the following wasnt also true:

    Under certain conditions DS/NS totally forgets about a machine. On first connect my understanding is that PXE checks to see if a PC is known or unknown...from this basis it either runs an initial deployment job or acts in a default manner.

    On restarting the PXE services a previously known machine WITH NO JOB SCHEDULED has the following happen to it:

    1) Hits PXE, no menu,
    2) Automation WInPE starts loading.
    3) WinPE loads. The PC stays here...forever, no IP job. no reboot.

    The long and the short of it chaps is that in this environment we have some PC's that 1rst boot device is NIC and some not. Either way, some will hit PXE... Whether they are known or not, what we have found is that DS7.1 mostly sends these machines off into some kind of purgatory and we never see them until they are restarted and forced into HDD boot. these are PC's with no job sceduled in DS - ie they are expected to just be told to boot to next device by PXE.

    Its a convincing reason not to use 7.1 and a rather scary option to enable on an enterprise of 11,000 clients. Our contractor is leaving site tomorrow none the wiser.

    Our collective thinking is that PXE thinks its an unknown PC but half way through realises it isnt and gets stuck. We believe there to be a mechanism that the Site server uses to build a list of PC's that are known and this process is not running correctly, especially in time for that first boot connection.

    Any thoughts, advice, whinges, even some laughter or "i told you so" would be appreciated :)


  • 2.  RE: PXE strange responses

    Posted Aug 26, 2010 01:34 PM

    On the PXE configuration you can check or uncheck the option to respond to uknown clients.  That should at least remedy part of the problem.  I am still testing and trying to get PXE to work in 7.1 to confirm the menu you speak about.  However, I did see something similiar to the menu option you have seen.  If your DS 6.9 PXE server is up and running and your trying to really boot into the PXE 7.1 world, you probably want to make sure that the 6.9 PXE services are off.  Even though my DHCP server had Option 60 (Option 66 on Windows Server 2008), pointing to my DS 7.1 SBS (PXE) server, the DS 6.9 PXE server was still getting picked up by my test clients.  That could of been the reason you say you "Initially during testing we got the same type of F8 prompt menu on first PXE connect that i got in 6.9. Then at some stage during configuration it stopped appearing completely."


  • 3.  RE: PXE strange responses

    Posted Aug 27, 2010 04:58 AM
    Hi thanks for reply.
    Switching off response to known clients only prevents us from imaging unknown clients. It doesnt help us stop sending known clients to WinPE. Sending known clients to automation partition via WinPE is the main problem as it delays boot time by some 5 minutes whilst the user scratches their heads and generates lots of helpdesk calls :)

    The two sets of services are not on at the same time. When 6.9 is on it responds as normal with the initial F8 menu and a selection of boot images. 7.1 just doesnt give that option at all now. And depending on its mood will just boot a PC to WinPE and do nothing.

    We can get the correct action to occur under the same configuration if we wait some time. but its a bit random when it works.

    Symantec folks seem to think theres something wrong/corrupt with PXE as its not expected behaviour but we are yet to speak to them due to the time zone difference in Lindon.


  • 4.  RE: PXE strange responses

    Posted Aug 31, 2010 12:24 PM
    Depending on your workstation branding, you can control the boot sequence and route past the network boot once the workstation is imaged. we have mostly Dell and control the BIOS/boot option through NS policy.  otherwise, i would think that any machine that had a live record in the DS would know to boot through/past the network boot into the OS.  you're saying that even with a live record AND with no jobs waiting on the machine, you're still seeing some machines boot to an image queue?


  • 5.  RE: PXE strange responses

    Posted Aug 31, 2010 06:22 PM
    I have seen this recently.  It does seem to recur particularly when there is a stop/start of the PxE/SBS service.  It did not seem to affect every workstations, but I have not been able to notice a pattern.

    You can remedey it to known clients by assigning a "Boot to Production" task.  This seems to work whether it is stuck in WinPE waiting for an automation task, or the computer is powered off -it appears this task affects both the client side through the task server and the PxE Server through the Task Handler.  Note that if the machine is booted to "Production" already, the task seems to fail with Error -1.

    I would be keen to read an exhaustive reference from Symantec on how the new PxE/SBS services function.  The danger of WinPE "boot loops" is high.

    David Merril


  • 6.  RE: PXE strange responses

    Posted Oct 15, 2010 07:18 AM

    Eventually got to the bottom of this. The cause was the behaviour of the PXE response to known or unknown PC's. The confusion arose because there are two servers on this site in question; one of them the NS.

    The client.SBS file is populated with known PC's shortly after the services are switched on. However there is a stored procedure that runs to assign the known PC's to the PXE server so it knows which are managed.

    http://www.symantec.com/docs/TECH133468

    that article explains a bit about the SP.

    Anyway being that the NS and a site server were both serving PC's on this site it was complete luck of the draw as to wether the PC i booted to PXE was known or unknown...depending on what task server had recently been serving it.

    The reason for the loops were that the job for unknown PC's was to boot to WinPE. The PC was known, but the details were not in the client file because the subnet was not right. The article shows how to change this process slightly. If you have pxe services off though on another server or the NS it will still cause issues with known PC's being treated as unknown.

     

    However this doesnt explain abotu the disappearing F8 menu. I can only assume this is connected to the original confusion as now I cant get rid of it again :)