Steps how to enable PXE on a distribution point in SCCM 2012
1. Add the Windows Deployment Services role to the server by using server manager.
2. From the SCCM Console: \Administration\Overview\Distribution Points
Right Click the DP and select properties.
Under the tab “PXE”, check “Enable PXE support for clients”
Check “Allow this distribution point to respond to incoming PXE Requests”
3. From the SCCM Console: \Software Library\Overview\Operating Systems\Boot Images
Right click the boot image and select “Properties”
On the “Data Source” tab mark
“Enable binary differential replication” and
“Deploy this boot image from the PXE service point”