Announcement

Collapse
No announcement yet.

force client to get dhcp address from different dhcp server

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • force client to get dhcp address from different dhcp server

    I currently have a windows 2003 DHCP server with the range 10.100.5.10 - 254. I setup DHCP on a windows 2008 server with IP address 10.100.14.10 - 10-254. How do I force the client to receive an IP address from the 10.100.14. 10 server. I setup reservations and added the MAC address and IP address. When I complete an IPCONFIG /release and renew, I get an IP address from the 10.100.5.0 dhcp server. Thanks

  • #2
    Re: force client to get dhcp address from different dhcp server

    You can't.

    By design a client will broadcast looking for a DHCP address. The DHCP server is listening for this broadcast and will reply. The first one to reply is usually the one to give the IP address.

    Comment


    • #3
      Re: force client to get dhcp address from different dhcp server

      Thanks for the reply. I guess I could down the dhcp server that I don't want to hand out an address. I just want to test the 2008 dhcp server. It will be my backup dhcp.

      Comment


      • #4
        Re: force client to get dhcp address from different dhcp server

        Yep, you must take the first DHCP server offline.

        In fact, I'm surprised your second DHCP server has been allowed to function by the domain - AD will disable non-authorised domain controllers.
        Please do show your appreciation to those who assist you by leaving Rep Point https://www.petri.com/forums/core/im.../icon_beer.gif

        Comment


        • #5
          Re: force client to get dhcp address from different dhcp server

          A dhcp client will ask the original dhcp server for an ip address, if there is no reply it will do a broadcast.

          Comment


          • #6
            Re: force client to get dhcp address from different dhcp server

            Originally posted by danjwalker View Post
            A dhcp client will ask the original dhcp server for an ip address, if there is no reply it will do a broadcast.
            Only when it does a renew

            Comment


            • #7
              Re: force client to get dhcp address from different dhcp server

              Few things:
              - what is your Subnet Mask? Are the two scopes on the same subnet?
              - what is the IP of the 2008 DHCP server? Is it in the the same subnet with the scope it serves?

              As it was previously said, this is something you cannot do. But you can try to "fool the system". This is what I would try:
              * on the 2003 DHCP server, delete the leased address of the test computer and change the available addresses' number such that it will have no available addresses to give. Turn on the test computer. It will first try to get its old IP back, but since it will get a No-No from its original DHCP, it will broadcast for other servers with available addresses.
              It might work, it might not. But worth giving it a try.
              If it won't work, disable the 2003 DHCP for few minutes and test the new one.

              Sorin Solomon


              In order to succeed, your desire for success should be greater than your fear of failure.
              -

              Comment


              • #8
                Re: force client to get dhcp address from different dhcp server

                Moving thread to DHCP forum
                Tom Jones
                MCT, MCSE (2000:Security & 2003), MCSA:Security & Messaging, MCDBA, MCDST, MCITP(EA, EMA, SA, EDA, ES, CS), MCTS, MCP, Sec+
                PhD, MSc, FIAP, MIITT
                IT Trainer / Consultant
                Ossian Ltd
                Scotland

                ** Remember to give credit where credit is due and leave reputation points where appropriate **

                Comment


                • #9
                  Re: force client to get dhcp address from different dhcp server

                  Sorry, I have been very busy and have not found the time to reply. Thanks for replying....
                  Basically my configuration on the windows 2008 server is the same as the 2003 server.
                  Configuration of the Windows 2008 that does not work:
                  IP address of 2008 server 152.xx.xx.234
                  super scoped- 10.100.14.10 -255

                  subnet for all devices: 255.255.255.0

                  Config of 2003 server that does work:
                  IP address of 2003 server 152.xx.xx.232
                  super scoped 10.100.14.10-255

                  All on the same wire

                  10.100.14.0 addresses are logical addresse (watchgaurd firewall)

                  From the Windows 2008 server I can ping the 10.100.15.0 network

                  No error on the server other than this error:
                  **This computer has at least one dynamically assigned IPv6 address.For reliable DHCPv6 server operation, you should use only static IPv6 addresses.

                  **The DHCP/BINL service on the local machine, belonging to the Windows Administrative domain school.net, has determined that it is authorized to start. It is servicing clients now.

                  I disabled DHCP on the working server for 10 minutes but no go. Tried ipconfig /renew and received no IP address

                  Again thanks for all the replies

                  Comment


                  • #10
                    Re: force client to get dhcp address from different dhcp server

                    If you want DHCP redundancy why not just spilt the Scope or even change the Mask to 254 and have them both running as is.
                    1 1 was a racehorse.
                    2 2 was 1 2.
                    1 1 1 1 race 1 day,
                    2 2 1 1 2

                    Comment


                    • #11
                      Re: force client to get dhcp address from different dhcp server

                      That is my plan but first I need to get the windows 2008 dhcp to respond to a client request. I have stopped the windows 2003 dhcp server and tested ipconfig /release and renew and can not get a response from the 2k8 server.

                      Comment


                      • #12
                        Re: force client to get dhcp address from different dhcp server

                        Is the server authorised and the scope activated???

                        Is the firewall running on the 2k8 server???

                        Comment


                        • #13
                          Re: force client to get dhcp address from different dhcp server

                          Originally posted by superhl View Post
                          From the Windows 2008 server I can ping the 10.100.15.0 network
                          Is this a typo? Should it have been 10.100.14.0 network?

                          I think it's time for some drill-down work. Are you accustomed with WireShark? I would download and install it (or use the portable version) and do some test on the issue. Let's start seeing where are the packets spending their time instead of getting that IP ...

                          Sorin Solomon


                          In order to succeed, your desire for success should be greater than your fear of failure.
                          -

                          Comment


                          • #14
                            Re: force client to get dhcp address from different dhcp server

                            Should have been 10.100.14.0. I have wireshark and hopefully test this week.

                            Comment


                            • #15
                              Re: force client to get dhcp address from different dhcp server

                              Just ran wireshark on the same switch as the server connection. I see communication between the client and .232 DHCP server but nothing from the .234 windows 2008 dhcp server.

                              Comment

                              Working...
                              X