I’ve kept getting the following error repeatedly, which is annoying because I deliberately rebuilt my test CM box in order to get rid of it (no pun intended). What was happening was that I’d create my test Hyper-V VM, remove the built in NIC and add the legacy NIC (for PXE) then boot the machine up. What happened next is (roughly) outlined in the following screen shots:
I say roughly, irritatingly I forgot to screenshot my equivalent of the second picture, so I “borrowed” image 2 from http://adventuresinosd.blogspot.co.uk/2011/03/troubleshooting-pxe-in-sccm-osd-part-3.html (the error I was getting wasn’t identical, but near enough).
Anyway, given this was a brand-new SCCM server I thought there must be something obvious to make this go away. I vaguely remembered something about anonymous access to the distribution point (possibly from www.windows-noob.com). So I went to Administration > Distribution Points, right clicked my sole (test) DP and chose properties. Ticked the “Allow clients to connect anonymously” tick-box and that did it- all of a sudden PXE is working. What’s weird is that PXE still works absolutely fine even after I’ve un-ticked the same box… no idea why but I don’t care, it works (this is the reason I had to use image 2 as I could no longer re-create the error I was getting to screenshot it).