Morning, It's a normal error, nothing usually to worry about especially if the devices continued to work. In some situation it does indicate networking issues, potential hacking/security but I would say from what you have described it's more a warning and that it was automatically fix itself.
>From what you described I would expected something similar to the following happened. 1) From what you describe I would say the device had been asleep for more than 24 hours 2) A new device (new as in not seen on the network for more than 24), was switched on Tech Details Below For Those Interested... ----- In standard consumer networking; 1) High level, computers usually talk to each other using host or domain names. e.g. www.google.com 2) Low level, computers usually talk to each other using IP address e.g. 74.125.132.104 (www.google.com current IP advertised to my laptop just now) 3) Hardware level, devices (computer/servers/routers/switches/hub) use MAC addresses. e.g. 01:23:45:67:89:0a 4) Computers don't need to use host or domain names, it's just more easier to remember a domain name instead of IP address. Also google might have several IP address, and which one you get might depend upon factors like your location or device type. 5) The only time you can't use host or domain names is when your configuring networking. 6) DHCP (Dynamic Host Configuration Protocol) basically automatically maps your MAC to a IP. 7) Router has say a MAC 01:23:45:67:89:0a an IP 10.1.1.1. 8) You connect your device to the router, in the default setup it will automatically basically says hello any DHCP servers out their to that network i'm a new device and my MAC is fe:dc:ba:09:87:65 9) If a DHCP server exists it will say yes, e.g. the router will answer basically saying i'm a router with MAC 01:23:45:67:89:0a and IP 10.1.1.1, please use IP 10.1.1.64 for your MAC fe:dc:ba:09:87:65. Plus other routing information along with how long you have that IP address for. DHCP service is configured with a number of IP address it is allowed to hand out, say anything from 10.1.1.64 to 10.1.1.127, so 64 IP addresses. 10) Your device wants to talk to google. Your device knows that is www.google.com currently is IP 74.125.132.104 so sends your request to that IP. 11) Your device hardware doesn't know what MAC that is for IP 74.125.132.104, so delegates that to your router. 12) Your device hardware then sends that request to your route IP 10.1.1.1 which is knows is MAC 01:23:45:67:89:0a. 13) Your router also also doesn't know what the MAC is for 74.125.132.104, and it is also a public IP address so knows to go off and delegate that request to your ISP. 14) This continues until a router/device knows the MAC address for the IP address, and so response. 15) Going past talking to google, if you now put that device to sleep and start another or wait for 24 hours basically the time it was told it was allowed the IP address for. 16) The new device also does DHCP and is given say 10.1.1.65 but the router might be trying to be cleaver and realise that 10.1.1.64 has not been connected to the networking for a few hours and so deem 10.1.1.64 is avaliable again and hand it back out. 17) The 1st device now starts up and continue to use fe:dc:ba:09:87:65 and 10.1.1.64, it will basically tell the router to keep sending traffic for 10.1.1.64 to fe:dc:ba:09:87:65. At which point the router says it's has two MAC address trying to claim traffic for the same IP. 18) Depending upon your router and devices what happens next will be different I realise those above steps have technical detail and in some places low level details and in others I've summaries what happens. But hopefully it briefly explains what happens and what is involves and anyone wanting more details can search for more details. In summary beware if sending anything to a domain name address starting http:// that is finance or personal. As looking back at step 14 your trusting a networking device configured by a person who could have incorrectly configured by mistake or on purpose. https:// is safer but their are still potential concerns, especially on shared computers or untrusted computers. On another note the following website does not exist http://www.nonexistingdomainnamerandomtext.com/ if you try to visit it should should get and error page which your browser decides. If you get any other page then that is probably your ISP inserting itself in between steps 1 and 2, where your browser tries to covert a domain name to an IP address. John On 20 November 2012 01:45, Stephen Watson <[email protected]> wrote: > Hi all, > > My partner woke his MacBook from sleep and it came up with a message to the > effect that "another device on this network is using the same IP address". He > saw the same message about two weeks ago, but we can't remember if it was > also when waking his Mac from sleep then. > > We are using a Netgear modem connected to an Airport Extreme and all > connected wirelessly. We also have two iOS device and another Mac connected. > I used to see the same message myself when I was in Brighton every couple of > months. > > What does it mean? What causes it? Is it any cause for concern and if so, is > there something we should do? > > Thanks very much. > > Stephen > > Right. Way past my bed ... Zzzzz > > > See my apps at www.blacktablet.co.uk > > -- > You received this message because you are subscribed to the Google Groups > "Sussex Mac User Group" group. > To post to this group, send an email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/smug?hl=en-GB. > -- You received this message because you are subscribed to the Google Groups "Sussex Mac User Group" group. To post to this group, send an email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/smug?hl=en-GB.
