I have a macbook (10.5.1), and I am trying to share my internet through Airport -> Macbook -> Ethernet Cable -> Xbox 360 to get onto Xbox Live. -What do I manually put as my IP? -Subnet Mask is 255.255.0.0 or is it 255.255.255.0 -What do I put as my gateway? Now, every time that my IP has confirmed, the DNS fails. How do I configure this properly?