If your Mac computer has an Internet from Chello, the only way to share it is the following steps: 1. Go to Control Panel (you find it in your Finder) 2. From the menu Internet and Network choose Sharing 3. After this step, you see on your Control Panel, a list of computer's sharing possibilities (File sharing, Web sharing, Screen Sharing and so on....) 4. Choose an Internet sharing 5. Define how to use an Internet together (through Ethernet in this case) 6. Define how the other computers get your Internet (throhgh Airport in this case) 7. Further more you could define a password in order to protect your connection from unknown users, or just leave without password if you dont mind that other unknown users use your Internet. That are probably all steps!!! And it should definitely work, if you follow this instruction clearly.