How do I share a wireless network connection with a wired device ?

[Linuxguy123]

I need a wired Ethernet connection between my laptop and a device.  

The device sends a high bandwidth UDP video stream to the laptop to save
on its hard drive.

The device also needs light, intermittent access to the Internet.  I
would like to provide this via the Wifi card in my laptop.

My laptop has a wireless card and a wired Ethernet device (NIC). I have
a crossover cable going between my laptop and the device.  I am running
F11 and network manager.

I found this article:

http://jeremy.visser.name/2009/03/24/simple-internet-connection-sharing-with-networkmanager/

Its interesting, but I think it misses a lot of details on how to set
this up.

I want my laptop to act as a DNS server to the device and allow it to
connect to the laptop via the crossover cable and the wired Ethernet
port.

I also want my laptop to connect to the Internet via the wireless card
and share that connection with the device.   

I've got my wireless connection up and running.  I've got the wired
connection to the device working, ie NetworkManager->Connection
Information shows an IP address, speed, etc. (IP address = 10.42.43.1)

I edited my wireless connection and set IPV4 Method to Shared to other
computer. 

I installed dnsmasq.  I turned on the DNSmasq server service.  

In system-config-firewall.py, I did the following:

- trusted the wired Ethernet port.
- trusted DNS and Multicast DNS
- turned on masquerading for the wired ethernet port
- applied all these

In spite of all this my device is not getting an IP address.   What am I
missing ?

How and what am I supposed to setup in the details for the wired
ethernet device ?  (ie NetworkManager-> Edit Connections-> Wired -> Edit
(device name)... 

It has fields for MAC address (blank),  MTU (automatic), 802.1x Security
(disabled) and IPV4 Settings Method (????).  If one selects Automatic
(DHCP), is that saying we are expecting another server to give this port
an IP address OR is that saying that the laptop will serve a DHCP
address to any computer that requests it ?   

I guess what I am asking is, how do I tell the laptop to serve addresses
to clients on the wired Ethernet port ?

Thanks !