1 Reply Latest reply: Feb 13, 2013 10:39 PM by wteiken
xyzzy Level 1 (10 points)

My iMac running Mountain Lion is connected to the rest of the network via an Airport Extreme.

Normally i use the ethernet connection for the communication. Tpday i noticed, that using the ethernet connection, the iMac has no IPv6 addresses configured.

If I enable the Wifi interface (to the very same Airport Extreme), the proper network prefixes are assigned to the iMac.


Both interfaces are configured to "Automatic".


sh-3.2# ifconfig en1


          ether 04:54:53:12:7c:56

          inet6 fe80::654:53ff:fe12:7c56%en1 prefixlen 64 scopeid 0x5

          inet netmask 0xffffff00 broadcast

          inet6 2002:5091:bb73::654:53ff:fe12:7c56 prefixlen 64

          inet6 2002:5091:bb73::3d66:4a75:7546:e7a1 prefixlen 64 autoconf temporary

          inet6 fd00::dead:beef:654:53ff:fe12:7c56 prefixlen 64 autoconf

          inet6 fd00::dead:beef:8564:e81f:5b29:16c9 prefixlen 64 autoconf temporary

          media: autoselect

          status: active


sh-3.2# ifconfig en0



          ether 3c:07:54:5c:68:8d

          inet6 fe80::3e07:54ff:fe5c:688d%en0 prefixlen 64 scopeid 0x4

          inet netmask 0xffffff00 broadcast

          media: autoselect (1000baseT <full-duplex,flow-control>)

          status: active

iMac (27-inch Mid 2011), OS X Mountain Lion (10.8.2)
  • wteiken Level 1 (0 points)

    It seems that some ethernet adapters (in my case two different USB ethernet adapters) loos IPv6 connectivity when the system goes to sleep, causing the adapters to permanently loose IPv6 connectivity until the next reboot.  This seems to be specific to individual adapters (i.e., the connectivity is lost for each adapter if connected while the mac is going to sleep).


    As a workaround I added a script that is executed on sleep (using sleepwatcher) that disables IPv6 on the interface.  When the system wakes up I re-enable IPv6 and then the adapter seems to properly regain IPv6 connectvity.