I think I need an IP address expert?

Discussion in 'iMac' started by anfield11, Oct 21, 2011.

  1. anfield11 macrumors 6502

    Sep 13, 2007
    Okay, I'll try and give as much information as I can here. This is happening on my iMac. I also have an iPhone 4S and an iPad 2. My network has a Time Capsule attached to it. All the software is updated to the latest and I've migrated to iCloud. My iPhone and iPad sync over wifi [a change I recently made from a wired sync]

    I am getting the following message on my iMac:

    "Another device on the network is using your computer’s IP address (192.xxx.2.12).

    Try connecting again later. If you continue to have problems, change the IP address of this computer or the IP address of the other device. Contact the network administrator if you need more information."

    If I reboot the iMac, the message still comes up. If I power off the iMac, router and Time Capsule it corrects and is fine until I leave the machine and it goes to sleep. When I wake it the message shows up again.

    I've put the x's in the IP address in case of privacy, and the numbers x'd are all the same in the info provided? I thought each piece of equipment had an IP address that couldn't be changed....the message is suggesting otherwise.

    The following is from System Information:

    IPv4 Addresses: 192.xxx.2.12
    Addresses: 192.xxx.2.12
    Configuration Method: DHCP
    Interface Name: en1
    Network Signature: IPv4.Router=192.xxx.2.1;IPv4.RouterHardwareAddress=00:1f:b3:16:43:11
    Router: 192.xxx.2.1
    Subnet Masks:
    Configuration Method: Automatic
    Domain Name: gateway.2wire.net
    Server Addresses: 192.xxx.2.1
    DHCP Server Responses:
    Domain Name: gateway.2wire.net
    Domain Name Servers: 192.xxx.2.1

    Any help greatly appreciated
  2. miles01110 macrumors Core


    Jul 24, 2006
    The Ivory Tower (I'm not coming down)
    Hardly matters. 192.168.x.x are generic IP addresses for private networks.

    If you change the network settings from "Use DHCP" (or whatever) to "manual" and put in a different IP address (keeping the subnet mask and default gateway the same) the error should go away.
  3. kalex macrumors 65816

    Oct 1, 2007
    you have 2 computers running same IP. Are you using DHCP or manually configure IP addresses on time capsule?

    Go through your devices and check which one of them is using static ip and not DHCP and u will find the culprit
  4. anfield11 thread starter macrumors 6502

    Sep 13, 2007

    LOL...so much for the privacy thing. Under network>TCP/IP it shows "using DHCP" IPv4 router There is an IPv6 under that, that has no information in it. Not sure where to look for the Time Capsule IP?


    Should have also asked what the "default gateway" is.
  5. anfield11 thread starter macrumors 6502

    Sep 13, 2007

    I'm not sure where to find the IP address for the Time Capsule [I have looked].

    When you say I have two computers using the same IP address, do you mean the iPhone and iPad as "computers?
  6. kalex macrumors 65816

    Oct 1, 2007
    time capsule is actually and is acting as your DHCP server and router. you have another device on your network that is using address. it could be your ipad,iphone or another device and its probably set as a static ip

    PS - yes by computers i mean any device that has an ip address :)
  7. anfield11 thread starter macrumors 6502

    Sep 13, 2007
    Thanks for responding again. Now to try and find out where the IP addresses on the iPhone and iPad are! :)

    As an aside, I have an apartment in my house and I let my tenant have access to my network using my password.....is there any chance that she is the offender? That said, I've had this arrangement with a number of tenants and never had this problem.



  8. kalex macrumors 65816

    Oct 1, 2007
    ah that makes sense. ok your devices are ok. Start talking to your tenants and see if u can figure out who is responsible. I bet you one of them set a static ip. or if you want an easier fix, assign a static ip to your imac and thats it.
    make it something else

    another option. shutdown your mac. install this app on your ipad http://itunes.apple.com/us/app/ip-network-scanner-lite/id335517828?mt=8 and scan your network. see if another device is on it with ip of your imac
  9. anfield11 thread starter macrumors 6502

    Sep 13, 2007

    Well, I just checked. She's not home and has a lap top that is with her...so not likely her. She also has an iPhone too, but I'm pretty sure she'll have that with her.

    Thanks for all this help, but not being a computer genius [although not dumb] how do i assign a static ip to the iMac? Do I assign it a number...i.e. make one up?
  10. kalex macrumors 65816

    Oct 1, 2007
    actually another question. how is your imac connected to the network? is it wired or wireless?
  11. anfield11 thread starter macrumors 6502

    Sep 13, 2007
    It's wireless.

    I downloaded that app...how cool is that! It shows:

    My router
    Apple TV...forgot that one
    HP Laserjet...forgot that one too! :)

    Oddly, the iPhone isn'f showing.

    They are all different IP's. Router is .1 iPad .10, would that be an issue? I haven't powered off the iMac though, but right now everything is working fine. Maybe if the message came up again then I should check the IP Network Scanner?

    Thanks for all your help.
  12. kalex macrumors 65816

    Oct 1, 2007
    they should be all different ips. each device has and only suppose to have 1 ip unless you are doing some sort of routing which you are not.
    Time capsule is and its your internet provider which means its a router. every computer connects through it to the internet.

    If everything is working now then your culprit is your tenant as she is not home at the moment :)

    See if u get an error when she is at home and as soon as u get an error disable wireless on your imac and scan again. see if anything is using .12 at that time.

    also double check and make sure that there is no cable in ethernet port on your imac :)
  13. anfield11 thread starter macrumors 6502

    Sep 13, 2007
    Ahhh, now I know why the iPhone isn't showing. The "Lite" version only shows 5 devices. But the IP is different.


    No, no ethernet cable in the in the ethernet port.

    Thanks very much, I should now be able to track the issue with that App you recommended. Thanks for your patience and help. Cheers
  14. kalex macrumors 65816

    Oct 1, 2007
  15. anfield11 thread starter macrumors 6502

    Sep 13, 2007
    Will do.

    I even upgraded the IP Scanner, as I have more than 5 devices....it's amazing how many you do have when you start to think about it.

    Anyway, no issues for now, but usually had occurred when the iMac went to sleep.
  16. fat jez macrumors 68000

    fat jez

    Jun 24, 2010
    Glasgow, UK
    That is one weird set of IP addresses. Are you sure you are using DHCP? I would have expected (unless you have a lot of devices you aren't telling us about) that the addresses would be roughly consecutive, e.g.


  17. kalex macrumors 65816

    Oct 1, 2007
    Not really. Depends on his dhcp scope and other devices that might have been registered before
  18. anfield11 thread starter macrumors 6502

    Sep 13, 2007
    Okay as a follow up to this.

    The problem is still lingering even if sporadic. When I went to the bigger IP Scanner it allowed me to see everything and showed as follows:

    ISP Modem.
    Apple TV.
    HP Laser.
    Time Capsule

    When the problem arises their are no "foreign" devices.

    In a recent check though, an odd thing happened. The IP's for the iMac and the Time Capsule were reversed. Is this the normal for IP'S to change, or an indication of the problem.

    These issues have only arisen since downloading all the new software and the changing from an iPhone 4 to a 4S.

    Any help appreciated.
  19. kalex macrumors 65816

    Oct 1, 2007
    Wait are u using time capsule as a router or are u using ISP modem as router? If u want PM me
  20. swiftaw macrumors 603


    Jan 31, 2005
    Omaha, NE, USA
    I wonder if you have DHCP turned on on both the ISP modem and the time capsule.
  21. kalex macrumors 65816

    Oct 1, 2007

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