AirPort Extreme MAC Cloning Issue

Discussion in 'Mac Accessories' started by Brian Y, Mar 6, 2013.

  1. Brian Y macrumors 68040

    Oct 21, 2012
    Hi All,

    I have a rather odd problem with my AirPort Extreme, and I simply cannot fathom what's causing it.

    I have an odd network setup (because I like configurability, but the AirPort Extreme is good for wireless): I have a regular router, with it's wifi disabled, and an AEBS, in bridge mode, wired into my router providing wireless. All works perfectly.

    Everything on my network has a static IP address. No static IP address = no connection (there is no reserve pool). It just makes it everything easier to manage remotely when I know the IP address of every computer and device). My network, briefly, is:

    MacBook in question:

    I've been getting a message coming up at random on my MacBook saying "Another device is using your IP Address" - which, in theory, is impossible - there are no other devices with that address assigned. When this happens, I also get this in the log:

    06/03/2013 22:29:54.000 kernel[0]: nd6_na_input: duplicate IP6 address fe80:0004::1610:9fff:fed6:3135

    IPv6 is disabled on my network - I have no need for it. When this happens, I checked what was connected to my router - and indeed, something was connected with ip address - and the MAC address of the device using it was that of my AirPort Extreme's 5GHz Wi-Fi card! So my AEBS has essentially stolen my laptop's static IP address (the AEBS is statically assigned, so shouldn't change from this). This isn't simply because it's connected through the Wi-Fi card - it lists the Mac of the device not the Wi-Fi bridge, and I can point AirPort Utility to and it will load up my AirPort Extreme Configuration.

    I've checked every possible configuration option on both routers, and I cannot physically see anything that's causing it - does anyone have any suggestions? I have literally run out of ideas with this one!

  2. drsox macrumors 65816


    Apr 29, 2011
    When you say that all your devices have static IP addresses, are they manually configured or are they configured on the router ?
    Do either of your routers have DHCP enabled ?
    Have you reset anything recently and not rebooted everything in the right order ?
  3. FreakinEurekan macrumors 68040


    Sep 8, 2011
    Eureka Springs, Arkansas
    You must have something (your router probably) that is serving DHCP. Set the DHCP range to something outside the range where you assign manual IPs, e.g. make the DHCP range start at That way if something does grab an IP from DHCP it won't overlap with existing devices.

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