Airport Extreme not accessible but Internet is fine

Discussion in 'Mac Basics and Help' started by djuggler, Mar 27, 2015.

  1. djuggler, Mar 27, 2015
    Last edited: Mar 27, 2015

    djuggler macrumors newbie

    Mar 27, 2015
    Knoxville, TN USA
    I have an Airport Extreme 3TB router (Cortexiphan). Connected to it is a 4TB external HD (Hippocampus). The 3TB is devoted to Time Machine while the 4TB is a shared network drive.

    To extend the range in the house, I added an Airport Express (Walternate).

    Periodically, I find myself able to surf the Internet and even look through the Time Machine history but unable to see the 4TB shared drive nor the data portion of the 3TB hard drive.

    The Macbook Pro 15" Retina acts like the Airport Extreme isn't on the network. Even Airport Utility shows it inaccessible with the message "Cortexiphan was previously part of your network. Check that it is still in range of your network and plugged into a power outlet. Forgetting this device removes it from this network."

    If I powercycle the Airport Extreme (Cortexiphan), everything works as expected.

    What could be going on?

    Before powercycle:

    After powercycle:
  2. satcomer, Mar 28, 2015
    Last edited: Mar 28, 2015

    satcomer macrumors 603


    Feb 19, 2008
    The Finger Lakes Region
    Sounds like either a cache file was corrupted or you were in a " double NAT" error in your home network setup.

    The rule of thumb is the device closet to to a modem should be running NAT and the Apple router beyond the first router Should not be running NAT. In an Apple Airport setup Apple calls turning off NAT " Bridged Network".
  3. djuggler thread starter macrumors newbie

    Mar 27, 2015
    Knoxville, TN USA
    I think you nailed it. I had forgotten that to be able to use the Uverse apps on the iPhone to control the TV that they had to be "on the same network" so the trick was to put the Airport Extreme into Bridge mode and let the Uverse router/modem combination serve the DHCP.

    I'll set the Airport Extreme back to NAT and see if that fixes the problem.


    Ok. That resulted in a "Double NAT" error. I'm going to have to remember what setting I changed on the U-verse router before I get a valid test.

    We never use the app for controlling the tv and in a week and a half I'm switching back to Comcast and buying an ARRIS / Motorola SurfBoard SB6183 modem. I'll just have to remember that the Airport Extreme needs to control NAT.
  4. Altemose macrumors G3


    Mar 26, 2013
    Elkton, Maryland
    On the U-Verse router you can add the Extreme to the DMZ or use IP Passthrough mode depending on the model.

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