A client computer that's on a different subnet than a PXE-enabled distribution point doesn't receive a PXE boot request as expected. This issue occurs when the Enable a PXE responder without Windows Deployment Service option is set on the distribution point, and IP Helpers are used to route PXE requests.
Hotfix information for System Center Configuration Manager, version 1806
Microsoft Download Center
The following hotfix to resolve this problem is available for download from the Microsoft Download Center:
After you download this hotfix, see the following Microsoft Docs webpage for installation instructions:
For information about how to download Microsoft support files, click the following article number to view the article in the Microsoft Knowledge Base:
119591 How to obtain Microsoft support files from online services
To apply this hotfix, you must have System Center Configuration Manager, version 1806 installed.
You don't have to restart the computer after you apply this hotfix. However, the ConfigMgr PXE Responder Service must be manually restarted on all distribution points that have the Enable a PXE responder without Windows Deployment Service option set in order for changes to take effect.
Hotfix replacement information
This hotfix does not replace any previously released hotfix.
The English version of this update has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.