Internet sharing broken in Mountain Lion?

Discussion in 'OS X Mountain Lion (10.8)' started by AhmedFaisal, Aug 22, 2012.

  1. AhmedFaisal Guest

    On my MacBook Air after upgrading to Mountain Lion I can no longer share my internet connection (USB Ethernet) via WiFi. The moment I turn it on, neither the MacBook Air itself or any of the devices connecting through the wireless connection can access the internet at all. Worked fine before on Lion so I am wondering if there is a bug....
  2. omgo macrumors newbie

    Oct 23, 2010
    I think it is broken indeed. I have to unplug ethernet, turn off wifi, turn off wifi sharing and then turn everything on, do it twice and then maybe my ipod touch and another macbook air running lion can connect. or sometimes there seems to be a connection, but DNS is not working..
    its a mess:((

    edit: on the other hand, there is finally WPA option in Mountain Lion internet sharing.. so far there was only WEP
  3. Wordman macrumors member

    Jan 14, 2010

    I had the same problem.

    After scouting around some forums, I activated the wifi monitor that's new to Mountain Lion. Not sure if it's a coincidence or not, but my Internet Sharing seems to now be working on one click of my wifi icon.

    Previously, I had to switch it off and on again every time I booted up my iMac.

    Curiously, the wifi icon has now changed. In Snow Leopard, it was just the 'fan' icon in black. Now it's grey with a white arrow in it.
  4. CHFeatherstone macrumors newbie

    Nov 1, 2012
    Figured It Out

    Make sure to manually assign the DNS of whatever you are connecting to the internet with (in my case, the Clear modem) via ethernet is the same as the DNS in whatever device wants to share the connection.

    On the Mac:
    System Preferences > Network > Ethernet > Advanced > DNS

    On my iPhone:
    Settings > Wi-Fi > [Name of Shared Network] > DNS

    Make sure they match. Mountain Lion 10.8.2 does not do this. For example, sharing told my iPhone the DNS server was, which is not the DNS address of the Clear modem. So, I manually changed it on the iPhone. It appears, so far, that so long as the iPhone remembers the shared network, it remembers the right DNS address. But I had it forget the network, and it proceeded to forget the right DNS address.

    I'm hoping this is a bug, and not a feature. ;)

  5. nefa macrumors member

    Aug 16, 2011
    Wow, thanks so much, you fixed it for me! I had to restart the sharing all the time and now it seems to work!
  6. Andreore macrumors newbie


    Aug 21, 2013
    Copenhagen (DK)
    Easier way

    For whom is still struggling with this issue, I found a much more practical way to do it (and possibly, the correct way) here. :)

    Hope that helps others.

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