I have a Raspberry Pi running Linux (Raspbian) which is connected to my corporate Internet over an Ethernet cable. The RPi also has a wifi adaptor plugged into a USB port. I've been following along the with Ada Fruit's Raspberry Pi Access Point Tutorial, but there is a snag.
I only want to allow connections from the wifi USB adaptor to reach services running on the RPi. I don't want them to be allowed to connect to the corporate network in any way. The RPi is running a service which should be available both over the corporate intranet and over the wifi connection. The RPi must not route any connection between the wifi network and the corporate intranet.
My question is, what part of the tutorial should I follow, and should I not follow to make this setup work?