PXE DP sends wrong UEFI boot file to client

Question

PXE DP sends wrong UEFI boot file to client

Franz Schenk 341

Have added a DP in another network with activated PXE option, and also selected "enable a PXE responder without WDS". Can't see any errors in the Site about this DP.

PXE boot does not work, getting PXE-E16 error.

A network trace of the DHCP traffic clearly shows that the client gets the correct, configured DHCP option 067, bootfile name "smsboot\x64\bootmgfw.efi
The SCCM DP is ignoring this DHCP option and the DP smspxe.log clearly shows that the DP sends the wrong bootfile name to the client. wdsmgfw.efi is the bootfile name for a WDS server.

Thank you in advance for any help
Franz

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Answer 1

Jason Sandys 31,406 Microsoft Employee Moderator

and that these options should be confgured on the IP helpers

There are no options to configure on ip helpers. That's part of the point in using them.

Most IP helpers do not support configuring these options at all. Thats why that everyone struggles around with PXE boot problems.

As above, you don't need these options when using IP Helpers, that's the point of using them. The NBP is automatically chosen based on the hardware architecture of the system being PXE booted. This is how PXE was designed to work.

Lots of details from the developer responsible for most of this at https://techcommunity.microsoft.com/t5/configuration-manager-blog/you-want-to-pxe-boot-don-t-use-dhcp-options/ba-p/275562.

Franz Schenk 341 Reputation points

2022-09-09T17:43:20.927+00:00
Thank you for the very informative link!

The information looks logical, but it didn't work for us with just configuring IP helper with the addresses of the DHCP- and the SCCM PXE DP.

We have a server network 10.100.10.0/24. The DHCP server has the IP 10.100.10.10, the SCCM PXE DP 10.100.10.30

The clients are in a network 10.100.50.0/24

The customer confirmed that he had configued a DHCP helper in the 10.100.50.0 network with the two IP addresses of the DHCP Server and the SCCM DP.

PXE boot didn't work with this configuration. According smspxe.log, the client never contacted the SCCM DP.
After configuring the three DHCP Options 60, 66 and 67 on the DHCP server, PXE boot works.

We have another client network, 192.168.50.0/24 and another server network 192.168.10.0/24. in this server network, we installed another SCCM PXE DP. And a DHCP server is also in this network. A DHCP relay agent is also configured in the 192.168.50.0 network, with the IP addresses 192.168.10.10 (DHCP server in the 192 network), 10.100.10.10 and 10.100.10.30. And with or without configuring the three DHCP Options 60, 66 and 67 on the DHCP server in the 192 network, PXE boot doesn't work, with the descibed behaviour in this question.
Jason Sandys 31,406 Reputation points Microsoft Employee Moderator

2022-09-09T18:43:20.51+00:00

PXE boot didn't work with this configuration. According smspxe.log, the client never contacted the SCCM DP.

I'm not a network configuration expert and this is very specific to the network equipment involved, but this literally works for every other customer in the world including every customer I've every worked with directly. Additionally, it's completely independent from Microsoft or ConfigMgr so I can only assume there's a configuration issue that the network team must track down. This may include actually tracing traffic as well as it's not the PXE booted client's job nor the PXE server's job to deliver the traffic but is instead the network's job.
Franz Schenk 341 Reputation points

2022-09-10T16:34:10.49+00:00

Thank you Jason! Will ask the customer to verify the network- and DHCP helper configuration again.

Answer 2

KurtBMayer 841

@Franz Schenk

For UEFI, it's not recommended to use DHCP options anymore. Although they may work in some circumstances, in others it can cause issues, perhaps like those you're mentioning.

The better approach is to set ip helpers on the switch to point to the IP. WDS will then auto-determine if the endpoint supports UEFI or BIOS and dynamically hand out the correct boot initiator and WIM.

Otherwise, perhaps refresh your boot images in WDS if needed. Or ensure the device is fully set to UEFI mode (no CSM or legacy boot settings should be enabled).

Please upvote or accept this thread as answered if it's helpful, thanks!

Franz Schenk 341 Reputation points

2022-09-08T18:56:10.837+00:00
Thank you for your feedback.

Theory: Microsoft says since years that these DHCP options for PXE boot are not supported, and that these options should be confgured on the IP helpers.

Practice: Most IP helpers do not support configuring these options at all. Thats why that everyone struggles around with PXE boot problems.

At the moment, we are using USB sticks for booting the PE Image

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PXE DP sends wrong UEFI boot file to client

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