As I’m getting some questions lately about the DHCP Options in combination with PXE Service Points (PSP), I decided to devote this post to those possibilities. When talking about a PSP and DHCP Options, there are three often used options:
- 060 = client Identifier (PXEClient)
- 066 = boot server host name
- 067 = boot file name
Now lets start with saying: “It shouldn’t be necessary to make manual additions to the DHCP Options on the DHCP Server”. Now I can already hear the questions pop-up, what about a combined server of DHCP and WDS/PSP, what about crossing over subnets and vlans, etc., etc.. These are all good and justified questions, but not necessary.
DHCP Option 060
In case there is a combined server of DHCP and WDS/PSP, then there is the need for a DHCP Option 060 (client identifier), but as I stated “no manual additions”. This all gets done by the installation of the PSP. Just follow these steps and no manual addition is needed:
- Install WDS and do not configure it.
- (Optional) Restart the server.
- Install PXE Service Point (takes care of creating DHCP Option 060).
- Change the REGVALUE UseDHCPPorts to 0. This value can be found in: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WDSServer\Providers\WDSPXE
- Run the command: WDSUTIL /Set-Server /UseDHCPPorts:No /DHCPOption60:Yes
- (Optional) Restart the server.
DHCP Option 066 and 067
In case there is traffic crossing over subnets and vlans then then there is the need for a DHCP Option 066 (boot server host name) and 067 (boot file name). Okay, I do admit that it’s easy to configure DHCP Options in this case, but also not necessary… Its mentioned multiple times, even by Microsoft (http://support.microsoft.com/kb/926172), that DHCP Options are not as reliable as IP Helpers. So i would always advise to use IP Helpers instead of DHCP Options.
Now to conclude my story I would like to say that: “It shouldn’t be necessary to make manual additions to the DHCP Options on the DHCP Server”.
More information about Planning for PXE Initiated Operating System Deployment: http://technet.microsoft.com/en-us/library/bb680753.aspx