Internet sharing

Hey there Zeratok,

Thank you for using Apple Support Communities 🙂

I recommend this troubleshooting found in the article named Wi-Fi: How to troubleshoot Wi-Fi connectivity found here http://support.apple.com/kb/HT4628?viewlocale=en_US.

1. Does the symptom occur with more than one Wi-Fi device?
   
   • Wi-Fi issues may be related to the network in question or they may be related to the Wi-Fi computer joining that network. Usually, if other computers or devices (such as the Apple TV or iPhone) are able to get on the Internet without issues, then your Wi-Fi router is probably fine.
   • If you only have one Wi-Fi device, proceed with this article.
2. Make sure your software is up-to-date.
   
   • Install all software updates available for your Mac.
   • If you use a third-party Wi-Fi router, check with the manufacturer to confirm that it has the latest firmware installed. If an update is available, follow the manufacturer's instructions for updating the firmware.
   • To determine if your Apple Wi-Fi base station firmware is up-to-date, see Updating your software.
3. Check your connections.
   

   Some networking issues may be caused by loose or disconnected cables. Verify that all Ethernet and power cables connected between your modem and your Wi-Fi router are correct. Checking that devices such as your router and modem are on, disconnecting and carefully reconnecting Ethernet cables, and/or replacing damaged Ethernet cables may resolve the issue without any further troubleshooting.

4. Verify that you are using the recommended settings for your device.

   See Recommended settings for Wi-Fi routers and access points.

5. Restart your network devices.

   Powering your modem or router off for a few seconds and then on again may resolve network issues without any additional troubleshooting. If you have phone service through your ISP, power cycling your modem may interrupt that service. You may need to contact your ISP in order to restore your phone service if your modem is reset or powered off. Ensure that you have alternative means to contact your ISP (such as a cell phone) to avoid unnecessary delays in restoring your Internet or phone

If needed, I would also recommend the troubleshooting from down toward the bottom of the article:

Symptom: The network connection drops unexpectedly

• Your Mac may not not stay connected to your Wi-Fi network reliably.
• Your Mac may stop accessing the Internet during use.

Solution

Use these steps if your computer disconnects from its Wi-Fi network unexpectedly.

1. Check your range to the Wi-Fi router and reduce the effect of interference.If your computer is too far from your Wi-Fi router or your environment has too much Wi-Fi interference, then your computer may not detect the Wi-Fi network properly. The easiest way to check for range limits with your Wi-Fi network is to move your computer or your Wi-Fi router closer together and make sure that there are no obstructions (such as walls, cabinets, and so forth) between the router and your computer.See Potential sources of wireless interference for more information about interference and solutions.
2. Try connecting to a different Wi-Fi network. If your computer works fine when connected to a different Wi-Fi network, then the issue may be related to your network router or ISP. In that case, contact the manufacturer of your router or your ISP.

If that does not resolve the issue, then I would use the Wireless diagnostics tool buit into Mountain Lion.

About Wireless Diagnostics

http://support.apple.com/kb/HT5606

Regards,

Sterling

Hi Zeratok,

Since mountain lion it does not work anymore. At the begining I could make it work sometimes, but now it really doesn't ever work. As soon as I share the internet, I lose my connection to the internet even on my Mac. My mobile phone recognizes the Wifi-spot, connects to it, but is without Internet as well.

This is exactly what's happening to me. Internet sharing worked for a while, but now it kills my internet connection on my Mac. But internet sharing does work on my late 2006 MacBook which is still on Snow Leopard. Really annoying to say the least...