kevin fromcamarillo

Q: what is "double NAT"?

setting up wireless network:

TWC router(wife disabled)+Apple Extreme(wifi enabled)+switch= various rooms. Have one Airport Express hardwired into wall far from Extreme.

Base station showing red. When open status, states "double NAT". What is this and why?

Thank you.

Posted on Jun 17, 2015 12:41 PM

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Q: what is "double NAT"?

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  • by Bob Timmons,Helpful

    Bob Timmons Bob Timmons Jun 17, 2015 1:04 PM in response to kevin fromcamarillo
    Level 10 (105,203 points)
    Wireless
    Jun 17, 2015 1:04 PM in response to kevin fromcamarillo

    A router supplies different and distinct services to a network to allow devices to connect.  To do this,  it provides DHCP service, which is the process of assigning IP addresses to each network device.  It also supplies NAT service, which allows the single IP address that your Internet Service Provides, to be shared with multiple devices on a network.

     

    If you see a Double NAT message, that would be telling you that you have two devices on the same network and both of them are trying to act like a router. That can create conflicts and other problems since  you only want one device on a home network to act as the router.

     

    You may  be able to get away with a Double NAT on a simple home network, so if you see no ill effects, you can run the network that way.  If you want to correct the Double NAT situation, you need to turn "off" DHCP and NAT on the AirPort Extreme.  That will place the AirPort Extreme in what is known as "Bridge Mode".

     

    That way, you only have one device acting as the router on the network.  If you want to do this.....

     

    Open AirPort Utility, click on the AirPort Extreme icon, then click Edit in the smaller window that appears

    Click the Network tab at the top of the next window

    Change the setting for Router Mode from the current DHCP and NAT to read "Off (Bridge Mode)"

    Click Update at the lower right of the window

    Wait a minute for the AirPort to restart and you will see a nice, bright green light. That is a good thing to see.

    Bridge Mode.png

  • by kevin fromcamarillo,

    kevin fromcamarillo kevin fromcamarillo Jun 18, 2015 7:24 AM in response to kevin fromcamarillo
    Level 1 (9 points)
    Desktops
    Jun 18, 2015 7:24 AM in response to kevin fromcamarillo

    Thank you. Yes, "bridge mode". Should have known. Any device(after router) has to act as bridge. Got it. Thank you again.