It’s sad but true: there are still many conference centers, hotels, and office buildings that lack Wi-Fi. However, many of these do offer hardwired internet access via Ethernet or (egads) a dial-up connection. If you’re solo, this is only a minor inconvenience. However, if you’re traveling or working with other people, a single wired connection can be a major productivity block.
Fortunately, Mac OS X makes it easy to share a single wired internet connection over a Mac’s built-in AirPort wireless card, to other computers that also have wireless capabilities. Except for the Mac Pro, every Mac released since early 2006 has featured a built-in AirPort card (which is what Apple calls its brand of wireless card).
This tip works best from a wired Ethernet internet connection, but I’ve read that it will also work with a cellular internet connection, such as those provided by Verizon, Sprint, etc.
To share an internet connection via a Mac’s Wi-Fi, first connect the Ethernet cable to the Mac that will be serving as the base station.
Next, navigate to that Mac’s System Preferences panel (found under the Apple in the upper left corner of the screen) and select Sharing. When the Sharing panel opens, select Internet Sharing (note that you won’t be able to check the Internet Sharing box until other options are configured). Next, make sure “Share your connection from: Ethernet” is selected in the drop-down list.
Since we want to share our Mac’s connection wirelessly, click AirPort in the “To Computers using:” box. Finally, click the AirPort Options button to give your new network a name and password. When you have everything the way you like it, turn Internet sharing on.
The Mac serving as base station will still be able to surf the web while others piggyback on its internet connection. Any device with Wi-Fi (including the iPhone and iPod touch) will be able to share this connection.