Setting up PXE Boot with IP helper

[danny_mccaslin]

I am very new at this, and I can't find a scenario that matches mine so I thought I would post a new question. We have two vlans, call them 17 and 20. Clients are in vlan 17 and receive DHCP addresses from the router. We stood up a Microsoft WDS server in vlan 20. How do I configure ip helper-address to use the server on vlan 20 for PXE while using the router as a DHCP server? One recommendation said to use two IP helper addresses with the PXE server first but that was for a setup with 3 vlans with the clients, DHCP, and PXE separated. Do I do the same here? Also, will that affect regular clients trying to get DHCP addresses?

[Alex Pfeil]

You will want to just setup options on the existing DCHP server. This will not affect other clients. Please see this post:

"you need to set options 66 and 67, 66 will be the IP address of yoru WDS server and 67 is the location of the boot file. should be something like

"boot\x86\wdsnbp.com"." https://community.spiceworks.com/topic/283044-wds-setup-with-separate-dhcp-server

Found on Spiceworks: https://community.spiceworks.com/topic/283044-wds-setup-with-separate-dhcp-server?utm_source=copy_paste&utm_campaign=growth

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[danny_mccaslin]

I've read that Microsoft doesn't explicitly support DHCP options though. Will that be a problem?

[Alex Pfeil]

I have used the IP helper-address to point to a Microsoft DHCP server for a few different products over 15 years and it has worked every time. You can also use a Cisco router as a DHCP server and place options on it as well. However, using the existing DHCP server that you have will usually be the best bet.

You can use 2 ip dhcp-helper addresses on a router, and it will work.  Do not set the options on the existing server and place them on the new one only. The problem would be that the new server could hand out a DHCP address to an existing computer if it responds first.

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[danny_mccaslin]

So would the thing to do be to set the first IP helper as the PXE server with the second being the DHCP server? So the traffic would leave the client, go out to the gateway pxe server for pxe boot, and back to the dhcp server to get its address.

[Alex Pfeil]

IP helper addresses can be listed in any order on a router. It will send the request to every helper-address in the list at the same time.