6 Replies Latest reply: Feb 5, 2008 3:32 PM by jeffjohn
Jmiller1138 Level 1 Level 1 (0 points)
I recently set up DSL service in my apartment. I have ATT yahoo DSL modem, and an Airport extreme base station plugged into it. The network works fine with my Vista PC connected to it, but when I try to connect my macbook to the network I get errors telling me the IP address the macbook wants to use is already in use, and my PC gives me an IP address conflict error.

The internet is fine, and the modem is configured automatically, so I think it must be a problem with the way the network is set up or the network settings on my macbook...

any ideas?

Macbook, Mac OS X (10.5)
  • Duane Level 10 Level 10 (117,950 points)
    Jmiller1138, Welcome to the discussion area!

    It sounds like you either you have your DSL modem connected to one of the LAN ports on the AirPort Extreme base station (AEBS) OR you have the AEBS configured to operate as a bridge.

    So first verify that the DSL modem is connected to the AEBS's WAN port.

    Second configure the AEBS so that it is "sharing a single IP address". Also ensure that both your PC and MacBook are using DHCP to get an IP address from the AEBS.
  • Jmiller1138 Level 1 Level 1 (0 points)
    my DSL modem is connected to the WAN port, and i have the AEBS configured as a bridge beacuse of a double NAT error. So the fix for one problem is causing another.
  • Duane Level 10 Level 10 (117,950 points)
    The double NAT is a warning. In your case you need to ignore that warning.
  • Jmiller1138 Level 1 Level 1 (0 points)
    That fixed it.

  • art4mad Level 1 Level 1 (10 points)

    Please forgive the inquiry, but I have exactly this problem. My Actiontec DSL modem causes a "Double NAT" error in my AEBS. The odd thing is that everything seems to be working. All the Macs in my home get internet access. I have the follwoing configuration:

    - Actiontec M1000 DSL modem to Wan Port of
    - AEBS 1 (802.11) Set to create wireless network, allow for extended network
    - AEBS 2 and 3 (802.11) as remote extenders, both to extend WiFi and for ethernet ports for gaming and internet ready AV stuff.
    - Mac Pro via Ethernet cable to AEBS 1
    - Multiple iMacs/Macbook Pros connecting via wifi

    You advised here that this gentleman just ignore his warning. Why is that okay? Is it just some false alarm, or does it have any effect on the speed or stability of the network/internet connection?

    Any clarification would be greatly appreciated!
  • jeffjohn Level 1 Level 1 (0 points)

    I recently posted what I believe to be a similar/identical issue. See my post here: http://discussions.apple.com/thread.jspa?threadID=1378849

    I have not changed my AEBS to "Off (Bridge Mode)" yet, because everything currently 'works' but I continue to get the occasional "Double NAT" warning suggesting I switch the AEBS to bridge mode. When this happens, I lose connection to the internet and need to unplugged both the AEBS and my modem to re-establish a connection to the internet and the external HD I have connected to the AEBS.

    My question for Jmiller1138, do you continue to get the "Double NAT" warning even when you changed your AEBS to "Off (Bridge Mode)"? I am hesitant to change my AEBS to bridge mode since I'm assuming I'll need to totally reconfigure my entire network (meaning both the AirPort Extremes, my wireless HP printer, and my firewalls on my PCs).

    The ignoring of the warning (i.e. closing the AirPort Utility without updating the AEBS) is what triggers the need to reset my AEBS and modem. Not fun.

    I guess I'll just need to bite the bullet and set the AEBS to bridge mode . . . yes?