Mac OS X Share Wifi Internet With Computers & Macs Via Wifi Hotspot

If you own a MacBook or any Mac with a pre-installed or USB/PCI wireless adapter, and you are able to use it to connect to a WiFi network, chances are you can also use it to share your internet connection with others (if you are connected to the Internet via USB modem or Ethernet cable, for example). This mode is sometimes called ad-hoc mode or creating a WiFi hotspot, and even though this feature was added to the iPhone only recently, but Mac OS X has supported this for a very long time.

Here are the steps to create a WiFi hotspot on Mac OS X:

  1. Check that you are connected to Internet via Ethernet, USB modem or Bluetooth tethering. It is impossible to be connected to the Internet via Airport (WiFi) and also share via Airport.
  2. Using Spotlight (or you favorite application launcher), navigate to the Sharing preferences pane in System Preferences.
  3. Click the tick mark next to the ‘Internet Sharing’.
  4. Select the appropriate source in the ‘Share your connection from’ drop down list. In my case, this was the Ethernet.
  5. Mac OS X allows you to share via multiple methods simultaneously. You can select as many options to share your connection. If you want to just create a WiFi hotspot, tick the ‘Airport’ option.
  6. You can choose to leave your hotspot open, or you may use standard encryption methods such as WEP, WPA to set a security passkey system.

Once the hotspot is created, you will see an upwards arrow sign on the Airport icon in the menu bar. This confirms that your WiFi hotspot has been created.

To connect to this hotspot, use your other device and locate the name of the WiFi network you just created, and connect to it like you normally would to any WiFi network. This setup should automatically provide a DHCP server, so you don’t have to bother with IP address settings.

Wireless Network Discovery & Connecting Software For Mac OS X

Recently, we talked about a quick way to view detailed stats for wireless networks that are available on your Mac OS X system. Though usually such detailed information is not needed, but enthusiasts or professionals might want to play around with wireless networks for educational motives, and another great tool which facilitates easy network discovery (and much more) on Mac OS X is KisMAC.

Be warned: KisMAC is no ordinary playtool, and this is probably evident from its first launch and home window. As soon as you fire it up, KisMAC gets to business, and is ready to start scanning wireless networks that are available at your current location.

As soon as you push the ‘Start Scan’ button, KisMAC begins to search for various wireless networks, and quickly displays various details about them, updating them in realtime. We covered a description of what these terms mean in my previous post. A great feature here is that KisMAC somehow manages to sniff out the SSIDs of hidden networks too (which explicitly hide or block their SSID for security reasons).

But this is just a preview of what KisMAC is capable of. KisMAC supports packet injection (only with supported cards capable of packet injection, such as Prism2 and some Ralink cards), which effectively means that you can use it a tool to crack the key for WEP or WPA networks, by brute force methods. You can learn more about WEP/WPA hacking and packet injection here. A word of advice though: its probably not a good idea to go around cracking people’s wireless network’s keys, and might even be illegal in your country.

Apart from this, KisMAC has support for geo-location and tagging (provided a GPS receiver is attached) of available wireless networks, and can also show you the range of a particular network on the map. KisMAC can also show you the list of logged in clients for a particular network and their IP addresses.

Although KisMAC is great at detecting your networking hardware, but in the rare case it does not pick up your card, you can set it up manually in the Preferences.

Download KisMAC

Quick View Detailed WiFi Network Information In Mac OS X

Not a day goes by when I don’t discover something new about Mac OS X. Its full of surprise functionality, each small detail aimed at making the life of Mac users just a bit more easier everyday.

I discovered this nifty trick courtesy Calling All Geeks, which is a nice portal for short tips/hacks or tutorials.

Normally when you click on the Airport icon in your status bar, you get a list of available Wi-Fi networks, with an visual indicator of their signal strength and a padlock depending upon the fact whether a particular network is open or encrypted. This is usually enough information, but sometimes you want to view more stats about the networks.

To do this, the usual way is to open up System Profiler (In /Applications/Utilities), go to the Airport tab, and then look at the details, something like this:

While this is a complete view of all the details about a network, there is a quicker way to view the advanced details of the currently joined network. All you have to do is hold down the Option key on your keyboard and then click the Airport icon. The stats for the currently joined network are now displayed inline.

The details displayed are:

  • PHY Mode: Shows the wireless standard of the network. Would be 802.11a/b/g/n.
  • BSSID: This is the MAC address of the wireless router or access point you are connected to.
  • Channel: The wireless channel that your router is configured to broadcast on. Usually a value between 1-13.
  • Security: The type of encryption used by the network. Could be open, WEP, WPA, WPA2.
  • RSSI: This is your signal strength. The perfect strength is 0. So -100 means a weaker signal than -50.
  • Transmit Rate: This is the max network speed available with the current signal strength. The data rate is measured in Mbps.

(Source: Calling All Geeks)