Network computers auto assigning IP address

Question

I'm administering 300+ MacBook in a 1 to 1 class room setting. for 3 months I had no problems, but more and more laptops are coming up with self-assigned IP address with no warning or reason. users (students and teachers) do not have admin authority to change settings so when it happens I have to physically (can't vnc to a deadend...) go and set TCP/IP to automatic and apply.
Previous years we used windows platform laptops and never had this issue so I'm hesitent to think its DHCP running out of lease IPs (I've checked it too)
If lowering the lease time so that if a student DOES self assign IP it wont be for long is a solution I'd be able to do so, but it seems rediculous to me that with DHCP, proper net setup, and adaquate wireless access point coverage (on uninterfering channels) that the macbook would rather make up some random garbage IP then just keep trying at DHCP....
the self assigned IP isn't even in the ip range so even if it DID do it network connection would never work anyway.
Any idea what I can do to NOT have the macbooks go auto assign IP (which is the dumbest thing I've ever seen) and keep their dhcp lease intact or reassign?

Answer 1

Welcome to Apple Discussions:
A "self-assigned" IP means that the computer is not able to reach the DHCP server.
There is nothing "dumb" about it if you understand how networking works. It's a flag that something is wrong with the network and the computer is not connected to anything.
Of course the "self-assigned" IP is not in your network IP range. That's how it works.
If this problem is new, and you have not done anything, it may well be local RF interference blocking or jamming the WiFi signal.
You might consider installing some sniffers on a computer and checking what other signals are in the area that may be causing the problem. Anything from a leaky microwave oven, to student(s) using a cellphone(s) or BlueTooth devices can cause WiFi issues. Being near an airport, a fire or police station or other source or RF can also cause loss of signal.