WDS: DHCP configuration for UEFI


Windows Server 2019

Introduction

In this article, we will see how to configure the DHCP service so that you can use WDS to install Windows on computers with UEFI enabled, which is the case for Generation 2 virtual machines on Hyper-V.

In a “standard” Active Directory deployment where DHCP and WDS services are installed on different servers that are members of the domain, no configuration is required to boot on the network (PXE) with computers that do not use UEFI.

In an environment where multiple configurations coexist, a DHCP server configuration is required for the network boot to work without the need to disable UEFI on computers

DHCP service configuration

Option 60 – PXEClient

Option 60 must be added to the DHCP server only if it has the WDS role installed.

By default this option is not available the list.

To add it open a command prompt as administrator on the DHCP server and enter:

netsh
netsh>dhcp
netsh dhcp>server
netsh dhcp server>add optiondef 60 PXEClient STRING 0 comment=option added for PXE Support
netsh dhcp server>set optionvalue 60 STRING PXEClient 

Which gives in image :

Add option 60 at DHCP

Check that option 60 has been added, in my case it was added directly to the server options.

Option 60 added

If it is not added directly, check in the options that it is present :

option 60 available

Configuring a UEFI Provider Class

The classes allow users and providers to create policies based on the DHCP lease request or identification, which will allow us to identify the request from a UEFI PXE boot.

On the DHCP console, right-click on IPv4 1 and click on Define provider classes 2 .

define classes

Click on Add 1 to define a class.

Add class

Name the new PXEClient class UEFI x64 1 , in the Description area 2 and ASCII 3 enter PXEClient:Arch:00007 and click on OK 4 .

Configure class

The class is added 1 , click Close 2 .

class dhcp added

Configure a policy

On the DHCP console, expand the scope 1 where the policy is to be created, right click on Strategies 2 and click on New Policy 3 .

New policy

Name strategy 1 and click Next 2 .

Policy name

We will now indicate the conditions of the strategy, click on Add 1 .

add a condition

Configure the condition as shown below:

  • Criteria: Provider Class 1
  • Operator: Is equal to 2
  • Value: select the supplier class previously added 3
  • Check the box Add a wildcard (*) 4.

Click on Add 5.

Condition configuration

The value is added 1 , click OK 2 .

Value added

The condition of the policy has been added to identify UEFI x64 PXE requests. Click Next 1 .

Condition added

It is possible to configure an IP range in the scope for the policy if you wish. Select the option No 1 and click Next 2

Policy configuration

Now, we will configure DHCP options 66 and 67 to indicate the PXE server and the boot file.

Check option 66 1 and indicate the IP address of WDS server 2 .

DHCP - option 66

Check option 67 1 and indicate boot file 2 . For a WDS server and UEFI boot x64 enter: bootx64 wdsmgfw.efi. Click on next 3 .

DHCP - option 67

The different boot images are located in the RemoteInstall Boot <version> * folder on the WDS server.

A summary of the strategy is displayed, click Finish 1 to validate the addition.

Overview policy

The policy is added to the DHCP scope.

Policy added

The options configured in the policy are also visible in the extended options.

scope options

Conclusion

WDS services do not normally require DHCP configuration, and by experience the PXE boot responds more quickly with this configuration on machines with UEFI enabled.




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