The Apple MacBooks are able to share their Internet connection over Airport. Let’s say you have your MacBook plugged onto an Ethernet cable, or you have a USB Data Stick for mobile Internet, and you want to give your iPod Touch access to the net. This can be done.
There are, however, one or two things to watch out for.
Elsewhere on Best Mac Tips I have shared how to connect your iPod Touch to a MacBook for the purposes of syncing application data (i.e. syncing between the OS X and IOS versions of an application, like Things, OmniFocus, MacJournal and many more). What I have found is that if I connect an iPod touch to the MacBook that way (be using the “Create Network” feature in Airport), Internet sharing might fail to work even though it is activated.
The trick is to NOT connect your iPod Touch with the MacBook using the Create Network option. Rather turn off Airport, go to Sharing in the System Preferences, activate Internet Sharing, and if need be turn Airport back on. Now connect your iPod Touch to the MacBook airport connection that becomes available. It will have the same name as if you used “Create Network” but Internet sharing should now work correctly.
If you have problems getting Internet access to the iPod even though it is connected over Wifi to your computer, go into settings and bring up the details for the connection. Check the IP address. If it starts with 169 you have problems. This is a self-assigned IP address. It should start with either 10 or 192. Try to disconnect (even restart the iPod if necessary) and go through the process again.
I am writing this in reference to OS X 10.6.8 (but it may apply to other versions). I do not recall having this problem on 10.6.6, for instance. Just since 10.6.7 or .8. I understand some people with Lion starting having these issues too.
Some people have found that if they create and ad-hoc network (using Create Network under Airport) AND set it to require a password then the problem goes away. So try that too if you’re still having no luck. However, other folk have found it only works when WEP (password) is NOT enabled. So try both ways.
I realise this is one of my least helpful tips because I have not spelt out every detail nor used any images. If you find it hard to follow, let me know and I may upload a picture or two to make it clearer.
The info here: http://www.macsonly.com/060311.html might prove useful too.