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  • Strange dhcp issue

    I have strange DHCP isue with clients who have leases like :

    649C173F.mydomain.local and similar

    All client computers have dynamic IP addresses but I know their names and they are registered in AD. Printers also have static IP addresess. Does anyone have the idea abotu this strange problem???

  • #2
    Re: Strange dhcp issue

    Could there be another DHCP server on the network somewhere?

    When you say the printers have static addresses, are they actually *static* addresses, or have you set up reservations in DHCP? Try reserving IP addresses for your workstatons and see if that makes a difference. Is it just the hostname or the domain name as well that is odd?
    Gareth Howells

    BSc (Hons), MBCS, MCP, MCDST, ICCE

    Any advice is given in good faith and without warranty.

    Please give reputation points if somebody has helped you.

    "For by now I could have stretched out my hand and struck you and your people with a plague that would have wiped you off the Earth." (Exodus 9:15) - I could kill you with my thumb.

    "Everything that lives and moves will be food for you." (Genesis 9:3) - For every animal you don't eat, I'm going to eat three.

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    • #3
      Re: Strange dhcp issue

      These are domain names :

      strangenumber.mydomain.local

      Printers do have static IP adreses which are in exclusion range.

      I've just deleted these strange leases. We'll see what will hapen, because our workers are now out, and I hope that I will see which machines are causing troubles.

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      • #4
        Re: Strange dhcp issue

        Most of client computers are turned off and nothing. Strange leases do not come...

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        • #5
          Re: Strange dhcp issue

          Maybe someone who took their own client with them?
          Marcel
          Technical Consultant
          Netherlands
          http://www.phetios.com
          http://blog.nessus.nl

          MCITP(EA, SA), MCSA/E 2003:Security, CCNA, SNAF, DCUCI, CCSA/E/E+ (R60), VCP4/5, NCDA, NCIE - SAN, NCIE - BR, EMCPE
          "No matter how secure, there is always the human factor."

          "Enjoy life today, tomorrow may never come."
          "If you're going through hell, keep going. ~Winston Churchill"

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          • #6
            Re: Strange dhcp issue

            I haven't quite understand you?

            What do you mean by that?

            Comment


            • #7
              Re: Strange dhcp issue

              Maybe someone was using their own laptop, that they have now taken away with them.
              Gareth Howells

              BSc (Hons), MBCS, MCP, MCDST, ICCE

              Any advice is given in good faith and without warranty.

              Please give reputation points if somebody has helped you.

              "For by now I could have stretched out my hand and struck you and your people with a plague that would have wiped you off the Earth." (Exodus 9:15) - I could kill you with my thumb.

              "Everything that lives and moves will be food for you." (Genesis 9:3) - For every animal you don't eat, I'm going to eat three.

              Comment


              • #8
                Re: Strange dhcp issue

                Originally posted by bogi500 View Post
                I have strange DHCP isue with clients who have leases like :

                649C173F.mydomain.local and similar

                All client computers have dynamic IP addresses but I know their names and they are registered in AD. Printers also have static IP addresess. Does anyone have the idea abotu this strange problem???
                that is the name of the printer?
                it is nothing to do with DHCP, it just registers it's name, regardless if it is Static or not.
                try eliminating in the DNS the Unsecured Updates and switch it to "Secure Updates Only"
                and see if it changes anything, if not then it is not the Printers it is a client that is connected to the domain.
                any way check what IP that record points to and try to identify it in the DHCP logs or look at your network Switches , find the port and then find the Network outlet in the wall,
                and your got your answer.
                Last edited by Akila; 16th October 2008, 17:26.

                Comment


                • #9
                  Re: Strange dhcp issue

                  Do you have a VOIP phone system?

                  I've seen these types of addresses at client sites with VOIP systems. The phones use DHCP to get their IP address.

                  Comment


                  • #10
                    Re: Strange dhcp issue

                    Yes, we do have AVAYA IP phones and media gateway switch (on which our servers are connected too), but as far as I can remember they have static IP addresses. Also there are phones IP phones from another company in our group.

                    There were some laptops from our system integrators, but they have regular names.

                    I will update You tomorrow morning when I get to work.
                    Thank You for replies

                    Comment


                    • #11
                      Re: Strange dhcp issue

                      These strange numbers are still here... I hope that they are from VoIP phones, but they shouldnt be...

                      I hope that this is not dangerous, because I don't see any other clent maschines except ours.

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                      • #12
                        Re: Strange dhcp issue

                        Try something like Angry IP Scanner and see if it picks up any foreign clients on the network.
                        Gareth Howells

                        BSc (Hons), MBCS, MCP, MCDST, ICCE

                        Any advice is given in good faith and without warranty.

                        Please give reputation points if somebody has helped you.

                        "For by now I could have stretched out my hand and struck you and your people with a plague that would have wiped you off the Earth." (Exodus 9:15) - I could kill you with my thumb.

                        "Everything that lives and moves will be food for you." (Genesis 9:3) - For every animal you don't eat, I'm going to eat three.

                        Comment


                        • #13
                          Re: Strange dhcp issue

                          I did it. I have some 4 unknow clients on the network. O ne of them is this strange IP address. probably, other wuold be also, because i always delete their leases.

                          Could they be an IP phones or not?

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                          • #14
                            Re: Strange dhcp issue

                            Unplug the phones one at a time and see what disappears off the network.
                            Gareth Howells

                            BSc (Hons), MBCS, MCP, MCDST, ICCE

                            Any advice is given in good faith and without warranty.

                            Please give reputation points if somebody has helped you.

                            "For by now I could have stretched out my hand and struck you and your people with a plague that would have wiped you off the Earth." (Exodus 9:15) - I could kill you with my thumb.

                            "Everything that lives and moves will be food for you." (Genesis 9:3) - For every animal you don't eat, I'm going to eat three.

                            Comment


                            • #15
                              Re: Strange dhcp issue

                              Heheh, I will surely do it I hope that users will not go nuts...

                              It is strange when they go home, there is not any activity although their phones are on and computers are off.

                              Comment

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