bernard.huang

Q: Airport Extreme DHCP & NAT settings - can't change NAT's default IPs?

Hi,

 

  I'm trying to setup the airport extreme to be used for our office.

  Our office IP is 10.255.x.x

  When I am trying to setup DHCP & NAT, within the NAT options, there's only 10.0.x.x, 172.16.x.x and 192.168.x.x

 

  How can I get the NAT to have 10.255.x.x?

 

  Without the NAT settings, I can't get this Airport Extreme to assign out valid IP addresses, and therefore useless

MacBook Air, OS X El Capitan (10.11)

Posted on Sep 7, 2016 12:17 AM

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Q: Airport Extreme DHCP & NAT settings - can't change NAT's default IPs?

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  • by Bob Timmons,

    Bob Timmons Bob Timmons Sep 7, 2016 6:48 AM in response to bernard.huang
    Level 10 (104,879 points)
    Wireless
    Sep 7, 2016 6:48 AM in response to bernard.huang

    Sorry, but Apple will only allow 10.0.x.x addresses to be assigned by the AirPort Extreme.

  • by tygb ,

    tygb tygb Sep 7, 2016 8:42 AM in response to bernard.huang
    Level 1 (131 points)
    Sep 7, 2016 8:42 AM in response to bernard.huang

    Hello !

                Suggested article : AirPort Utility 6.x: Reserve a DHCP address for client computers

    Hope , so it can help you .

     

    Thanks !

  • by Bob Timmons,

    Bob Timmons Bob Timmons Sep 7, 2016 9:02 AM in response to tygb
    Level 10 (104,879 points)
    Wireless
    Sep 7, 2016 9:02 AM in response to tygb

    Unfortunately, the article does not mention that the only IP address range that can be assigned by the AirPort router when it is set up to provide DHCP and NAT service is 10.0.x.x, 192.168.x.x or 172.16.x.x

     

    Confirm by checking the settings in AirPort Utility to see that the "10.0" prefix, or "192.168" or "172.16" cannot be changed.

     

    Screen Shot 2016-09-07 at 10.53.44 AM.png

  • by LaPastenague,

    LaPastenague LaPastenague Sep 7, 2016 2:54 PM in response to bernard.huang
    Level 9 (52,260 points)
    Wireless
    Sep 7, 2016 2:54 PM in response to bernard.huang

    bernard.huang wrote:

     

    Hi,

     

      I'm trying to setup the airport extreme to be used for our office.

      Our office IP is 10.255.x.x

      When I am trying to setup DHCP & NAT, within the NAT options,

    This is actually easy if you remove NAT.

     

    DHCP is an option. You do not want or need NAT. Then you will have double NAT problems.

     

    So if you want Double NAT..

    The fact that the office uses 10.255.x.x. is irrelevant to devices behind the Extreme.. they may as well be on 192.168.x.x (and I highly recommend you do NOT use 10.x.x.x behind another 10.x.x.x because the Apple router doesn't like routing in that setup.. even if the subnet is correctly class C it works as if it is class A.

     

    In fact if the office is using 10.255.x.x then your Airport could also use a small range in the same IP subnet.

     

    Simply fix the main router to exclude a selection of addresses .. eg 10.255.1.1-200 is used by the main router.. and you can then set the AE statically to 201 and use DHCP on the network tab, to clients behind it from 202 - 254. It works fine as I have it running that way.

     

    Screen Shot 2016-09-08 at 7.52.56 AM.png

     

    Screen Shot 2016-09-08 at 7.53.15 AM.png

  • by Bob Timmons,

    Bob Timmons Bob Timmons Sep 7, 2016 4:18 PM in response to bernard.huang
    Level 10 (104,879 points)
    Wireless
    Sep 7, 2016 4:18 PM in response to bernard.huang

    Your original post stated that......

     

    "When I am trying to setup DHCP & NAT, within the NAT options, there's only 10.0.x.x, 172.16.x.x and 192.168.x.x"


    If you don't need the AirPort to provide NAT service, then LaPastenague has a good idea for you.