IP Address Issue, need help?

Discussion in 'MacBook Pro' started by CosmoPilot, Jan 9, 2011.

  1. CosmoPilot macrumors 65816

    CosmoPilot

    Joined:
    Nov 8, 2010
    Location:
    South Carolina
    #1
    Two days ago, I installed AppleTV at my house. Not sure if this is the culprit, but my issues started after it was installed.

    My MBP will works fine on my home network, then randomly loses the Internet connection. Today, I was able to catch an error message that stated another device was using my computers IP address. So, I checked the ATV, and it was not. Then, I checked my iPhone...and it was!

    I reset my modem, reconnected my MBP...everything was fine. I then turned on the screen to my iPhone and whaalaa! It happened again. I noticed the iPhone was using the same IP address as my MBP.

    This time, I reset the modem, and made sure my iPhone was using Wi-Fi when I did this. Now I'm up and running. All devices are set using DHCP. Would it be better to assign Static IP addresses?

    I've never done this, and don't want to screw anything up.

    At my house, I have a lot of wireless devices:
    3 laptops
    3 iPhones
    1 AppleTV
    1 iTouch 4G

    Plugged into the modem is my desktop computer and an AT&T Microcell.

    Would the addition of 1 more device (AppleTV) to my network start causing these problems?

    I really hate getting kicked off my own network.

    Thanks in advance!

    Cosmo
     
  2. SandboxGeneral Moderator

    SandboxGeneral

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    #2
    When you say modem, do you mean router?

    Which router do you have and what is the limit of devices it can handle at one time? Have you updated it to the latest firmware available for it?
     
  3. CosmoPilot thread starter macrumors 65816

    CosmoPilot

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    South Carolina
    #3
    Yes, router (sry). It's an AMBIT (provided by Comcast Cable). Don't know how many wireless devices are supported. It's currently up-to-date.

    thanks
     
  4. SandboxGeneral Moderator

    SandboxGeneral

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    #4
    Well it sounds like your router is failing somewhat. Routers are not supposed to be able to assign two like IP's via DHCP at the same time. It could be a combination of that and/or the iPhone or another device isn't releasing it's IP lease while the router is reassigning it. Or you could have too many devices where the router can't handle them all and its assigning two like IP's, but again, they're aren't supposed to do that.

    In technical reality, the only way two devices can have the same IP on the same network is if they were assigned statically on the device itself, then the conflict would arise most evidently.
     
  5. CosmoPilot thread starter macrumors 65816

    CosmoPilot

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    South Carolina
    #5
    That's what I thought, but after a quick Google search, some tech's recommend static IP assigning to prevent the router from doing just that and kicking you off the network.

    I've had this network running since June with absolutely no issues. Installed the AppleTV (and it is running beautifully...watching some Netflix movies right now). Then all of a sudden, I notice the MBP won't connect to the internet. It recognizes the SSID but gives an error message that another device was assigned this computers IP address.

    So, I reset the router and got the MBP up and running. Then when I turned the screen on to my iPhone (I believe Wi-Fi goes to sleep on it until woken up), the MBP lost the connection again. So I double checked, and sure enough, my iPhone was xxx.xxx.x.10 and so was my MBP. The second time, I made sure all Wi-Fi enabled devices were up and running when I reset it so each one would get a different address. But I don't have confidence now that this issue will stick, i.e. give me a long term solution.

    I was wondering how hard it is to assign static IP addresses to each Wi-Fi enabled device. What would be the advantages/disadvantages of doing so, etc.?

    Thanks again.
     
  6. nippyjun macrumors 65816

    Joined:
    Jul 26, 2007
    #6
    Wirelessly posted (Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_2_1 like Mac OS X; en-us) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8C148 Safari/6533.18.5)

    You could do a dhcp reservation instead of setting a static ip. Either method could work. You will need your router manual to see where to change the settings.
     
  7. CosmoPilot thread starter macrumors 65816

    CosmoPilot

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    #7
    ambit
     
  8. nippyjun macrumors 65816

    Joined:
    Jul 26, 2007
    #8
    Wirelessly posted (Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_2_1 like Mac OS X; en-us) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8C148 Safari/6533.18.5)

    Can you see a dhcp reservation section in the router settings?
     
  9. newdeal macrumors 68020

    Joined:
    Oct 21, 2009
    #9
    ...

    assign your devices static IPs and your problem is solved. Likely one of your devices already has a static IP and so when another connects to the network it takes that IP and causes issues. If you set all of them to have static IPs you won't have an issue anymore
     
  10. CosmoPilot thread starter macrumors 65816

    CosmoPilot

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    #10
    Under the DHCP settings, it has the range (0-153) and it has CPE's = 8 (don't know what this is? The devices that are currently connected, show up and it gives me the option to check a box next to each one and then select "force available."

    Will sharing these addresses (i.e., provide a picture) with you guys provide a security risk. Would be easier for me to just grab a photo and post it. Not sure if this is a good idea though.
     
  11. CosmoPilot thread starter macrumors 65816

    CosmoPilot

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    #11
    How do you do this? Do you have to tell the router as well as the devices?
     
  12. SandboxGeneral, Jan 9, 2011
    Last edited: Jan 9, 2011

    SandboxGeneral Moderator

    SandboxGeneral

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    #12
    The 0-153 is the numerical range of IP's that can be assigned in that subnet and that is the standard amount. I don't know what the CPE =8 is though.

    Sharing the addresses isn't necessary but if you do it's ok. Your IP's are either going to start with 192.168.50.XXX, 172.16.0.XXX, or 10.0.0.XXX. Those are the private subnets all routers have. You need not worry about posting those ever because they are not publicly routable and therefore cannot be used against you. There is also the private subnet 127.0.0.X but that is usually assigned for the local loopback on every computer.

    It should be really simple, usually there is just a drop down menu that shows you DHCP or static routing. When static is selected 3 fields should open up below, one for the IP, the next is the subnet (usually 255.255.255.0) and then one for the gateway (which will be your routers IP). Then below that you have the option to set by default up to two, sometimes more, DNS IP's for resolving domain names and public IP's. You can leave this as dynamic (DHCP) if you like. Find this spot and you can change your devices to statically assigned. Once you do that, you have to go into each device and do the same thing assigning the correct IP to the device that you programmed for it in the router.
     
  13. CosmoPilot thread starter macrumors 65816

    CosmoPilot

    Joined:
    Nov 8, 2010
    Location:
    South Carolina
    #13
    Great info, I found the DHCP drop down box to change to static. Right now, I'm still connected. If it does it again, I think I may give it a go.

    HOWEVER, I've been eyeballing an AirPort Extreme. Would I have similar issues if I got one of those and then just disabled WAN from my current router?

    The reason, is the current router only supports b/g I'd like to use N for my MBP and ATV.

    Given the randomness of this occurrence, and my desire to upgrade to the Airport Extreme, would you still recommend assigning Static IP addresses?

    And lastly, will assigning static IP addresses to individual devices cause issues when I venture out and find a public hot-spot?

    Thanks again for all the very useful information.

    Cosmo
     
  14. SandboxGeneral Moderator

    SandboxGeneral

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    #14
    I use the AEBS myself and have had it for about 5 years now. It's been a great and painless experience for me. I use it in DHCP and always have.

    I have on it:
    iMac
    MBP
    iPhone
    XBox 360
    Vista laptop
    Win7 PC
    Samsung BD player

    Even though my 3GS is only wireless G, I can still pick up my WiFi over 300 feet away from the AEBS - across the street. It's a great router to be sure.

    Why would you want to disable your WAN? If I understand that correctly, you will effectively disable your Internet connection. The only WAN thing you want disabled is WAN remote administration. That would leave a door open for an attacker to gain access to your network.

    When you set your static IP on your MBP you should setup in Network under System Preferences different "Locations". You can set one called "Home" and make that your static IP profile and then create another "Location" and leave that for the DHCP. When you leave the house you will need to go into the Network preferences and switch it and apply it. That's all you need to do. I have to do that between home and the office. At work everything is static IP.
     
  15. jenzjen macrumors 68000

    Joined:
    Aug 20, 2010
    #15
    Try this before you go down the static route, because even if you get the AE, your current router would still manage IP addresses assuming you would run the AE in bridge mode, so we still need to figure out if your router is really dying or just had a glitch.

    * go into every device that connects to your network, delete the network and power down the device

    * login to your router's admin utility and remove all IP addresses/connected devices ... if you want to be really thorough, choose a different name for the network

    * one at a time, turn on a device, connect it to the network and test to make sure you get internet ... rinse, repeat for all devices and *fingers crossed* once all your devices are on, you will not see an address conflict
     

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