Cannot boot to NetInstall image

I have one Mac Mini with Server installed and the NetInstall service On. It looks like this:  I plugged an ethernet cable into this Mini, and plugged the other end into a MacBook. I'm now trying to boot the MacBook to the netboot image. I tried holding down Option during boot; the only option I see is the local HDD. I tried holding down N during boot; it does not find anything. What else to I have to do to make this work? I tried turning on the DHCP server on the Mini but that doesn't seem to provide addresses to either machine. Not sure why auto-assigned addresses wouldn't work for this though, since this is just an isolated ad-hoc network. If this works I will add a network switch so I can do 5-10 Macs at once. So I'm not looking for an easier offline solution that will only let me do one at a time.