We use a separate wifi router and connect the clients to that for printing etc. - if they don't need internet access. If they need internet access we build our laptops with different boot partitions to fulfill the reqs. and then physically connect the wifi router to our internet
eg. Part1 - Internet and word
Part2 - No wordprocessing
Part3 - Wordprocessing
The exam officer is responsible for booting to the correct partition before the exam.
We tried setting each exam laptop up to save to a shared storage area on the network but found that it was best to get them to save to their desktop and then print from there.