WiFi is pretty ubiquitous these days, with devices that support WiFi and places that offer Internet over WiFi as a service, mushrooming everywhere.

At least that’s what I used to think till about last month when I found myself in a hotel with no WiFi and just one Ethernet port that I was expected to share with two of my friends. Now, we could all do what others at the venue were doing. Sharing the Ethernet port, finish up our work in a given time and hand over the port to the next in line.

Or we could just make one of the computers act as a WiFi hotspot and let the other PCs access the Internet through the first one.

It isn’t too difficult to guess the option that we chose, and for our little setup we decided to use my Mac as the router, since the setup was the easiest on the Mac.

In this post today, I’m going to detail the steps that are needed to share the Internet connection on a Mac effectively turning your Mac into a Wifi router.

First of all, you need to create a network of all the computers that are going to share the connection. In networking terms, this is called an adhoc network.

The good thing is that you don’t need to do anything special to create an adhoc network in OS X. OS X will prompt you when it needs to create one, if you’re using the Airport Card (WiFi) for sharing.

To enable Internet Sharing, open System Preferences (Apple -> System Preferences) and clickSharing.

Select Internet Sharing from the list of Services.

From the Drop down menu, select the Interface which is connected to the Internet source and from the list below it, select the interface which you want to share with the other computers. In my case, that was the Ethernet and the Airport (WiFi), respectively.

The third and final step is to create an adhoc network which the other computers can connect to.

Click on Airport Options.

OS X will then prompt you to type in a name for the new network.

Unless you want all the freeloaders in the neighborhood to piggyback on your network, I’d suggest that you select the Enable Encryption option and provide a password for the network.

That’ all there is to it. Click Ok and OS X will enable Internet Sharing on your Mac, from the Ethernet to the Airport Interface.

The only thing left now is to search for a new networks in all the other computers that you want to connect, and our adhoc network should show up in the list. Select and join this network.

All the client machines should now be able to browse the Internet as if they’re directly connected to the Internet over WiFi.