Every now and then I get the question about setting up your DHCP server for SCCM when the DHCP server doesn’t reside on the same host as the SCCM/WDS server.
So to get this working you need to set option 66 and option 67 in your DHCP server.
The options should be set to as following:
Option 66 (boot server host name): IP of your server, ex 10.0.0.1
Option 67 (bootfile name): SMSBoot\boot.sdi
There are many guides out there on this topic, but most don’t need or want to understand the inner workings of DHCP, they just want the filenames. So there you go.