Wednesday, July 23, 2008

Follow Up: Differential Analysis - WDS & DHCP

So I was doing some more reading about the WDS & DHCP service split Jason and I talked about in these two posts when I found a technet article that had some information in it that could have saved us some time. The section titled Known issues with configuring Windows Deployment Services says "If DHCP is installed on a server that is located in a different subnet, you will need to do one of the following ... Add DHCP options 66 and 67. Option 66 should be set to the Windows Deployment Services server, and option 67 should be set to boot\x86\"

The article also has a link
here to another technet article with more detailed information about network boot programs. After doing some further reading it turns out that the image has the following purposes:
1. Architecture detection
2. Pending computer scenarios. When the Auto-Add policy is enabled, it is sent to pending computers to pause the PXE boot and report back the client computer's architecture to the server.
3. PXE referral cases (including use of Dynamic Host Control Protocol (DHCP) options 66 and 67)

So I was able to setup a split WDS/DHCP environment in production, all of the packets were being passed from client to server based on my packet captures. The PCs that I am attempting to deploy to have an x64 architecture so based on Microsoft's documentation ("In addition, x64-based computers can run x86-based or x64-based boot images. Therefore, for each of these tasks, you could have two boot images—one for x86 and one for x64. The boot menu on x86-based computers will only display x86 boot images (because x86-based computers cannot run x64 boot images).") I should be fine using an x86 boot.wim to boot.

But when I go to boot the client into the default boot.wim boot image (taken from a 2008 Server DVD) it gets the following error:
WdsClient: An error occurred while communicating with the Windows Deployment Services server. Please check to ensure that the server is operational and that the necessary ports are open on the server's firewall. Server name [name], Server IP address [ip].

By hitting Shift+F10 I get a command shell where I checked for a valid IP address which I had.
Then I checked the detailed log file of the boot process in: x:\Windows\Panther\Setupact.log.

The very bottom of the log file has the following error messages:
Info "InitializeLogging: RPC_S_SERVER_UNABAILABLE - Retrying server request for initializing logging."
Error "CreateClientSession: Failed to initialize Client -> Server logging. Error code [0x800706BA].[gle=0x000006ba]"
Error "CreateClientSession: Failed to create client session. Error code [0x800706BA].[gle=0x000006ba]"
Error "CallBack_WdsClient_DetectWdsMode: Failed to create client session or initialize WDS unattend. Error [0x800706BA].[gle=0x000006ba]"

Now the weird thing is that I can boot to the capture.wim image (still x86) with no problems, so I did some more research and found out that this data was being blocked at the network...

Looking at some more documentation from Microsoft I see that the following ports must be open for WDS to work (the error message mentioned above was due to port 5040 needed for WDS to create an RPC connection being blocked):
  • UDP - 67, 68, 69, 4011
  • TCP - 135, 137, 138, 139, 5040

After changing the firewall rules everything started working again.


I hit another snag in the deployment. Now I have an image (52GB Vista Business) which I created overnight (I estimate it took about 5 or 6 hours to capture). I saved the initial WIM file to an external hard drive due to its size and overnight the connection to the server was lost so the image was not moved.

No big deal, I just simply plug the drive into the server go to WDS and import the new image into the new Image Group that I created.

So after this gets done I go and try to pull this image but when I boot the client up into the WDS PE boot environment I do not see any images (I should see two at this point).

Back to the server where I enabled trace logging on all the components with regarding to WDS, these are located in the registry under:


Just look for the keys that start with WDS.

These log files will turn up in %windir%\Tracing\

I found the following errors in the log:

[WdsImgSrv] Error in enumerating images. Error [13].

So I disabled all the images on the server and copied the new image from the USB drive onto the local hard drive then imported it into WDS under my original Image Group.

So this worked, the image pushed down in one and a half hours and everything worked.

Next up is documentation about MDT, AIK and Unattended installation of Vista and Server 2008.


Keydet89 said...


What's your email address?


ziedcrys said...

my firewall is disabled, but i get always the same you know why??
Thank you..

Tom Haskell said...

ziedcrys - Is the error you are talking about seeing "WdsClient: An error occurred while communicating with the Windows Deployment Services server. Please check to ensure that the server is operational and that the necessary ports are open on the server's firewall. Server name [name], Server IP address [ip]."? If not let me know what the error is.

You need to have a clean path from the server to client on the ports specified in the post, this includes both the server's firewall and any network firewalls. I also had a problem where the computers I was imaging were not able to get an IP address soon enough. If you hit Shift+F10 and check to see if the computer gets an IP address that could also be the problem.

Feel free to email me at if you need more assistance.