I have an MDT server with WDS setup to PXE boot over the network. It was originally setup on our 10.1.0.x network, but we migrated it out to a co-lo (192.168.250.x). All the networking is setup to talk to each other, DHCP/DNS is on our 10.1.0.x and after the migration PXE boot fails. From what I gather this is because the PXE broadcast from the client can't traverse different subnets. It looks like there are a few different solutions that I have found:

  • IP Helpers to point the broadcast to the WDS service
  • DHCP options 60,66,67 (not sure if needed in conjunction with IP helpers)
  • Setting up WDS service on 10.1.0.x subnet
  • DHCP relay agent

Some people recommend the DHCP options, and others say it isn't recommended. Do I have to have the IP helpers setup regardless of the options I choose, etc... I'm just kind of lost (obviously). Can someone point me in the right direction for the easiest way to get WDS/PXE running again?

2 Answers 2


You need IP Helpers on the routing gear pointing to your newly located WDS server.

BTW, IP Helpers == DHCP relay agent

  • Thanks for the reply! I set that up on the router, but still same issue. Do I need to setup a DHCP service on the WDS server too? There isn't DHCP on the 192 network it is all static.
    – Arpan3t
    Apr 24, 2019 at 16:32
  • off course you need a DHCP server with your WDS server; the DHCP will provide IPs and additional PXE info to booting PXE clientes like the IP address of the TFTP Server (WDS) and the NBP (Network boot program)
    – Pat
    Apr 24, 2019 at 19:37
  • No you don't. I setup DHCP on the WDS server and it still wouldn't connect. I disabled it and set the DHCP options on the other network's DHCP and it worked.
    – Arpan3t
    Apr 26, 2019 at 14:08
  • You had 2 DHCP servers feeding the same subnetwork? You do not know the topic but it seems despite your ignorance you like to lecture the ones that try to help you. Good luck.
    – Pat
    Apr 26, 2019 at 19:34

Okay I finally got this to work with a mixture of solutions. First set up the IP helper/DHCP relay on the router that communicates between the networks 10.1.x.x - 192.168.x.x. Then on the DHCP server add options 66 and put in the IP address or hostname of the server running WDS. Add DHCP option 67 and put in the bootfile location (/boot/x86/wdsnbp.com). Finally on the WDS server properties I had to change the blockfile size to 1024 and turn of variable window extension under TFTP because the bootfile kept failing to load halfway through. You do NOT need to have a DHCP server on both networks, I just have the one DHCP server on the network that the clients I'm imaging are on, and not on the network with WDS/MDT server. Hope this helps anyone setting up WDS/PXE booting across networks.

  • Microsoft recommends not using option 67/67, you'll have issues with UEFI clients.
    – Pat
    Apr 25, 2019 at 4:09
  • I read that, but MDT setup UEFI just fine. Trust me, I wish you had a solution instead of telling me what MS recommends.
    – Arpan3t
    Apr 26, 2019 at 14:04
  • I already gave you the solution with my answer.
    – Pat
    Apr 26, 2019 at 19:38

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