Setting Up a Specialized Wireless Hotspot/Bridge Combo for Work

Givens: So, where I work at has a number of separate networks.  There is a corporate network which has a number of security setups which need to be kept pristine.  There is also a guest network which uses a capture port wireless access.  I have a copy of Kali Linux on my work laptop which runs in a VM.  I want to keep this VM separate from the corporate network but still be able to use it in my job, which involves doing some checks against lab equipment.  I also like to bring my RPis into the office to work on during lunch.

Project:  What I want to do is use a Raspberry Pi to be the intermediary with two internal network connections at work with the following characteristics:

1. EXT - provide connection to the guest wireless through a wifi adapter on the RPi; have it automatically log into the guest wireless capture page and obtain an IP; this should provide a semi-permanent connection for both internal networks.
2. NET1 - provide a bridge to the Kali Linux VM through a USB to Ethernet adapter connected to the Ethernet port on the RPi and then to a USB port on the work laptop; have it provide the EXT IP directly to the Kali Linux VM.
3. NET2 - provide a NAT firewall (opt. packet inspection) between the EXT and another wifi adapter which provides a DHCP server/Wireless Access Port with an SSID which is common to the home network.  I might split this up into 3 separate SSIDs.
4. TUN1 - provide an opt. ssh tunnel through the EXT from NET2 to the home network for vpn connection giving an external WAP connection to my home network.

I already have the makings of this project by having a wifi hotspot configuration.  This configuration uses a D-Link DIR-505L router connected to the guest network.  It however, occurred to me that maybe I should do this with one single RPi and just keep the RPi at work.  I could power this up via a USB cable plugged into my laptop dock (A to micro USB cable).

I think I might dub this one Reverse Router, because I can think of a couple of other things that I might do with it under the area of penetration testing.

Update (2015-01-25): I had problems getting the DHCP server to work correctly and consistently with the TP-Link adapters that I was using, they kept dropping out.  I finally got a sufficiently consistent connection once I switched over to the Netgear adapters. I may end up having to buy additional adapters for other tests.

Update (2015-01-27):  I changed the channel addresses so that the two Netgear wifi adapters would not be tromping on each other; for stability reasons.  I found a website that tells me how to set up multiple SSIDs on the same interface using hostapd (Multiple_SSIDs_with_hostapd). Also finally got the basic wireless access point to work with a wireless connection to my DIR-505L router.  So now I have a wireless coming in to a NAT firewall to a WAP with DHCP going out.  Right now I am copying the microSD to put onto a different microSD so that I can implement multiple SSIDs.  What I want to do there is to have three SSIDs: one accessing the house (house SSID and cert), one for guest access, and one for secure test access (TBD).  Each of these SSIDs will be set up to appear if certain files have been touched.  I have not fully determined if the Netgear G54/N150 can handle multiple SSIDs or not.  I know that hostapd can.

Update (2015-01-28):  Well I discovered that there are some issues with changing the mac address of a wifi adapter on the fly.  I did the first part of the setup from the Multiple SSIDs with hostapd article and borked the connection.  What I will probably find when I look into it is that the wifi mac address was stored somewhere and it's keeping the dhcp server from running on the WAP.

Update (2015-01-29): Nope, the Netgear G54/N150 is not capable of changing the wifi MAC address; at least from my experiments that is the case.  I wish that were not true, maybe I will try the previous wifi adapters (based on the rtl8188cu chipset).

Update (2015-01-30):  After reading a couple of things online, maybe what I have here is a driver problem for the Netgear G54/N150 nano adapters.  What seems to give it away is the problems that I have when I try to use the "iw list" command, which always comes back with an error.  In addition, the setup does not appear stable between reboots; sometimes the dhcp server comes up and sometimes it doesn't.