Here’s the scenario that brought me to write this article: the ISP I’ve signed up with decided to temporarily block the internet connectivity in our area. Where I live, it’s actually possible — things like these do happen without reason. Because of that, Mark O’Neill suggested purchasing a UMTS device that would allow me to go online just about anywhere with reception. So I did. It costed me quite a bit but I thought it would be worth the money.
Now, here’s the tricky part. In my home network, we have 2 Macs and one PC running on Windows XP. The UMTS device connects via USB. How do we decide who gets to use it? We put our thinking caps on and finally decided that it would be easier to share the internet connection using one of the Macs. I rolled up my sleeves and got to work.
Internet sharing between Macs is basically very easy but if you add a Windows PC into the mix, things get a little problematic. Sharing the internet connection between Mac and PC turned out to be harder than I thought. I’ll explain why in a minute. But first, let’s just assume that we only needed to share the connection between 2 (or more) Macs via AirPort (WiFi). It’s very simple.
Open System Preferences and click on Sharing.
Before Internet Sharing can be enabled, you first have to configure the proper settings.

In the ‘Share your connection from’ dropdown list, select the port that has internet connectivity. In the screenshot above, I have “Ethernet” selected when it actually should be USB — ignore that. Then select how you would like to share the connectivity. I chose AirPort so that I can share the connection with several other computers. Checking the box next to ‘AirPort’ unbricks the ‘Airport options’ button.
Click on that button and configure your network name and security options.

Alright, here’s where the whole Windows and Mac concoction starts to rear its ugly head. Due to the different methods that the two operating systems deals with Hex encryption, the password you enter here will not be easily accepted by Windows. A Windows PC will be able to detect the wireless network but it will not be able to join.
Here’s the workaround. Select the 128-bit WEP encryption option and enter a 13-character password. Then, rename the network to something really short without spaces. When you’re done, hit OK.
Now you can check the box next to ‘Internet Sharing’. You may get a prompt to start AirPort, click Start. Right, the connection is shared. Macs detect the network automatically (and so will iPhones and iPod touches) and will connect to it as though it’s a regular router.
On the Windows PC, a little bit of manipulation is required. Turn on the wireless adapter and right-click on its taskbar icon to select “View available wireless networks”. In the subsequent window, click on “Change advanced settings”.
Click on the Wireless Networks tab and then click the ‘Add’ button to add our shared network.
Print the network name accurately, then set the network authentication to ‘Shared’, data encryption to ‘WEP’, uncheck the box next to “This key is provided for me automatically” and enter the 13-character password.
Click on the Authentication tab and disable IEEE 802.1x authentication. Next, click on the Connection tab and make sure that it will connect when in range. Click OK and apply the settings.
It should now try to connect to the shared AirPort connection. Cross your fingers. This sort of busts the myth that Macs and Windows won’t work well together 6 Things Windows Users should Know Before Switching to Mac 6 Things Windows Users should Know Before Switching to Mac Read More , doesn’t it?
I noted a few oddities during the whole procedure: 40-bit WEP encryption didn’t work when trying to share the internet connection between Macs and PC. The password was always incorrect. Then I changed it to 128-bit and everything was well. Also, the network name must not contain any spaces. The Windows PC wouldn’t connect to “Jackson Chung’s MacBook” but it connected with “jxn”.
How would you go about this procedure from a Window’s point of view? I would love to hear it. Tell me how — in the comments!
Bravo Jackson, excellent post. Worked for me.
I meant to add above that I was going to purchase an expensive Cradlepoint MBR1000 broadband router to accomplish this shared internet access but now it seems I do not need to.
However does anyone know if my download speed would be faster with the router vs the Airport?
Thanks.
Mark
Thank you for a very helpful and timely article. I needed to connect an iMac, iTouch, and Windows notebook and Nokia Smartphone to a new AT&T LightningConnect USB broadband.
I was able to get things going initially without security but when I added the 13 character security key nothing could access the internet - they connected to the Airport but nothing else.
I followed your instructions and everything is working!
I initially had a continuing problem with theTouch, which was docked. I pulled it out of the dock and retried and it was able to connect. So heads up on docks perhaps.
Thank you.
Marl
thank you - this was very helpful. I am sharing my pc connection with my MAC (which is using an aircard) so this worked out perfectly.
Thanks for this.
For all the people that said it was not a common situation - not so fast.
I'm travelling with my Mac laptop and was (easily) able to connect to the single ethernet cable at the hotel - since they do not offer wireless. But my kid was not able to get her windows PC to connect via the ethernet cable no matter what. So... I just shared the connection as per this article (didn't enable security, since it was just a short-term issue...). Worked like a charm!
Didn't work for me. Thanks anyway. "Windows unable to connect to the selected network" message is all i get )-:
Any advice would be great!
Wow!!! That worked!!! Thank you SO much!
hey i'm all conected up but now what??? how do i actually go about using the internet on my pc?
please help!
When you use 40-bit just specify the password in hexadecimal. So instead of using the numbers 0-9 you use 0-f (with f being 15 in decimal). So you would need a 10 digit hex number (every hex character is 4-bit) like: deadbeef08 or 0a1b2c3d4e
But how to enter a hex value in a Mac's Internet Sharing preferences? Just entering "0a1b2c3d4e" will not tell your Mac is not a plain text password. Maybe prefixing "$" or "0x" (zero-x) helps, but I cannot test that.
(Some more details on 5 or 13 character passwords are described in Apple's Choosing a password for networks that use Wired Equivalent Privacy (WEP). Some generic notes on entering hexadecimal keys on macosxhint.com in Entering a WEP hex key for preferred AirPort network.)
Excellent!!! Was a huge help! Thanks for the info!
It will be nice to see how configure network with Windows Seven and Snow Leopard
If you're using Windows 7 PC to connect to the 1 ethernet/internet connection and share the connection to the Mac (Snow Leopard), is easy. To do it with Snow Leopard as the first/sharing, that's another thing all together (haven't played with Snow Leopard yet).
Ugh.. WEP is a scary thought.. I hope MAC has WPA\2 option..
Hmm. I don't know about Macs, but... I think I'd just get a router that you're supposed to have anyway :o
Thanks Joshua, but this was a temporary problem. I do have a wireless router for my regular ISP. This article about achieving internet sharing from a USB UMTS device.
You know, there are some routers that include a USB port. That should have made the device accessible without going through all the grief you experienced.
Hi David,
There are some situations where this solution will come in handy. For example, when you're traveling and there's only ONE ethernet cable for internet but you have several computers and no router. I'm trying to show how you can set up an internet sharing connection spontaneously without the use of a router.
And sharing starting from a Mac, that's great. Thank you for sharing this idea. I'd like to use this for my boss' Mac, he travels a lot and a few friends. Its alright if I post this someplace else on-line? Thanks in advance -PC and Mac Consultant/tech
Thank you. I'm afraid you can't post this elsewhere. All published works are copyrighted. What you can do is post a link to this article.
Jackson I found your post very comprehensive and helpful however still cannot achieve a connection. As you mentioned i can see the mac from windows but cannot connect using a 40-bit WEP. I am therefore using a 128-bit WEP key with 13 characters. Now the PC cannot even see the Mac. When went back into the windows network connection to review the password it seems to have changed to only have 8 characters. I have tried several different combinations with the same result.