PXE-E51: No DHCP or proxyDHCP offers were recevied.

[andersonj]

I can import computer information into my collection once and it will PXE boot once. After the first time no matter if the computer successfully installed the image or failed I cannot boot into PXE anymore on that same computer. I can add a brand new computer out of the box and it will PXE boot one time.

 

I get the error bellow

DHCP...........

PXE-E51: No DHCP or proxyDHCP offers were received.

PXE-MOF: Exiting Intel Boot Agent

 

Why would it run once and get a DHPC address but then never run again? Shouldn't the SCCM server always send a DHCP request or shouldn’t my DHCP server? I might be missing some small configuration.

 

I am running SCCM 2012 RTM on Server 2008R2 RTM. Clean install from the ground up. WDS and DHCP are not on the same server but are in the same subnet. WDS service is started.

[Peter33]

SCCM 2012 is creating an "unknown" object for every device that boots via PXE and adds it to the collection "all desktop and server clients". Just delete this "unknown" entry and you will be able to PXE boot again.

[andersonj]

SCCM 2012 is creating an "unknown" object for every device that boots via PXE and adds it to the collection "all desktop and server clients". Just delete this "unknown" entry and you will be able to PXE boot again.

 

 

I did see an article with some users having the unknown computers issue. I do not get the unknown entries after the first PXE boot. I import my computer with a specific name. That computer does remain in its collection after one successful PXE boot. I never find those computers or unknown computers in the "all desktop and server clients" collection.

I did find some additional information from my troubleshooting. If I delete the computer from its SCCM deployment collection then re-add it by importing the Computer information, it will sometimes receive the DHCP request and boot into PXE. This could take a day of the computer being out of SCCM before I can add it back in to make it work. This sounds like the unknown computer issue but does not always work.

Is there a certain amount of time the computer need to be out of SCCM before it can be re-added to get the DHCP request again? Somehow I get the feeling I am missing a setting in SCCM that tells it to always accept DHCP request from clients.

Thanks,

[Rocket Man]

No once you delete the object fom the DB it should PXE boot straight away as an unknown client........Are you not using unknown computer support for PXE?? It sound way to much hassle to import computer info into sccm. Maybe you should enable this functionality as you'll find it is much more effecient.

 

 

I never find those computers or unknown computers in the "all desktop and server clients" collection.

 

Nor will you if it has been a successful build,...using unknown computer support will give you these objects...during the build process they will be seen as unknown clients if you do a search of all systems for them at OSD time.....after the process is finished they pick up their stamped name given to them at OSD time......If some fail then they will remain as unknown accounts(simply delete these to get them to PXE boot again)

 

Maybe by importing the info the way you are doing it does not show all this(not sure if SCCM uses a different type of process by importing computer info) but I would recommend enabling unknown computer support on your DP (you can lock it down if you are worried about staff accidentally/purposely F12 for PXE by simply adding a password on the PXE DP Point..

 

Rocket Man

[andersonj]

No once you delete the object fom the DB it should PXE boot straight away as an unknown client........Are you not using unknown computer support for PXE?? It sound way to much hassle to import computer info into sccm. Maybe you should enable this functionality as you'll find it is much more effecient.

 

 

 

 

Nor will you if it has been a successful build,...using unknown computer support will give you these objects...during the build process they will be seen as unknown clients if you do a search of all systems for them at OSD time.....after the process is finished they pick up their stamped name given to them at OSD time......If some fail then they will remain as unknown accounts(simply delete these to get them to PXE boot again)

 

Maybe by importing the info the way you are doing it does not show all this(not sure if SCCM uses a different type of process by importing computer info) but I would recommend enabling unknown computer support on your DP (you can lock it down if you are worried about staff accidentally/purposely F12 for PXE by simply adding a password on the PXE DP Point..

 

Rocket Man

 

 

 

I do have unknown computer support enabled.

 

I set might OSD tsk sequence to deploy to only one collection called Deploy HP Image. Then I import computers I want to image into that collection. It is a hassle but it’s safe.

 

How long should it take for SCCM 2012 to find an unknown computer once it’s been deleted from the database? I have had unknown computers setting idle for a while after I have deleted them and booted them into PXE without any luck.

[Rocket Man]

In one of my larger sites(single PS) with 15 remote DPs... if i delete a system from any of the remote sites on the PS and wait approx 2-3 mins sometimes less I can boot this system to PXE without failure....

 

 

I set might OSD tsk sequence to deploy to only one collection called Deploy HP Image. Then I import computers I want to image into that collection. It is a hassle but it’s safe.

 

Just set a password on the DP so that if a user does press f12 they will have to know the password to proceed(much the same outcome as above without the hassle) and in saying this it will also only boot if the computer is unknown, if it is known it will timeout and proceed to windows, of course once your TS is deployed and made available not mandatory to the unknown computer collection!!

 

Also you could make TS available to the unknown computer collection so the user can then choose which OS TS to install!

 

 

Also you say you have a premade collection that you import info into...i take it these are out of the box systems that you are importing and not systems that are already known to SCCM??

[andersonj]

In one of my larger sites(single PS) with 15 remote DPs... if i delete a system from any of the remote sites on the PS and wait approx 2-3 mins sometimes less I can boot this system to PXE without failure....

 

 

 

 

Just set a password on the DP so that if a user does press f12 they will have to know the password to proceed(much the same outcome as above without the hassle) and in saying this it will also only boot if the computer is unknown, if it is known it will timeout and proceed to windows, of course once your TS is deployed and made available not mandatory to the unknown computer collection!!

 

Also you could make TS available to the unknown computer collection so the user can then choose which OS TS to install!

 

 

Also you say you have a premade collection that you import info into...i take it these are out of the box systems that you are importing and not systems that are already known to SCCM??

[andersonj]

You are correct these are out of the box systems. Today I deployed my task sequence to the unknown computers collection. I restarted the computer I am trying to image and it does not boot into PXE. The computer will also not show up in the unknown computers collection. What configuration do I need to check if SCCM is not finding unknown computers and adding them to the unknown computers collection.

[Adminoob]

I had the same problem and found this thread, only to realize that my issue was caused by our DHCP server running out of IP's! Sometimes it is the simple things that elude us.