WDS + MDT + ISC DHCP + Single VLAN — UEFI won't boot 0x102

Question

Hello there!

I'm trying to implement Windows Deploy in my network, but struggling with network settings i must use to correctly set up WDS+MDT PXE deploy

What do i have:

• Linux Gateway with ISC DHCP Server in use
• Allied Telesis switches as access switches
• VM with Server 2019 (also tried 2022) with WDS role and MDT installed, connected to one of the switches

VM is getting DHCP address 10.0.32.100 which is bound for it's MAC.

I'm trying to deploy OS into a laptop which is getting it's IP in the same VLAN 10.0.32.X/24 via UEFI PXEv4 boot. It sees the server and stuck at "Contacting WDS server" state resulting 0x102 error (AFAIK it stands for timeout or communication error).

But! As soon as i connect this PC directly (using L2 "dumb" switch between Hypervisor and client PC) it boots perfectly.

DHCP server got it's option "next-server" set to Server's IP. I knew about ip helpers, but i didn't quite understood how should i use it and, if so, where to implement it, as soon as our switches have nothing to do with DHCP traffic.

I used tcpdump on a linux gateway and WireShark on the Server to see is there is any difference in traffic between Server and Client PC when it's connected directly and separetly. It turned out to be pretty much the same: First goes DHCP DORA, then some TFTP traffic, then once again DHCP request-ack stage when client PC at the "Contacting WDS server" state. And i noticed when client and server are separeted this last DHCP request-ack stage is looped until client get 0x102 and quits.

I can't quite understand why it's happening, cause it looks like Allied Telesis switches blocking DHCP traffic from/to Server, even though there's no such thing set up on them.

Do i miss something? In other words: how would i set up WDS+MDT PXE booting using ISC DHCP correctly?

Should i use IP helpers? If so, where exactly?

Any advice is much appreciated, thanks in advanced!

P.S.

Forgot to mention that BIOS clients is booting with no problem, which makes it so much stupid to me to understand why...

Answer 1

Hi,

Per my experience, it's recommended to use IP helper for your scenario. Your DHCP server and each PXE server should have an entry in the IP helper tables. That way, the DHCP server and PXE server will get the client boot discovery and request, and only the server that needs to respond will respond. The configuration is like this:

IP helper-address <IP address of DHCP server>

IP helper-address <IP address of PXE server>

IP forward-protocol UDP 4011

For more information, please refer to: IP Helper-Address Configuration for PXE Boot

Note: This is non-Microsoft link, just for your reference. Thanks for your time,

Best regards,

Simon

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Answer 2

Hi,

Hope everything goes well. Do you need any further assistance about this issue? If yes, please feel free to let us know, we will do our best to help you.

If the response is helpful, it's appreciated that you could click "Accept Answer" and upvote it, this will help other users to search for useful information more quickly.

Thanks for your time.

Best regards,

Simon