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  • #2092655

    DHCP server is giving itself a second IP

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    by rob baugh ·

    My DHCP server is setup with a Static IP. That IP is reserved for the DHCP. The DHCP however has set the IP to an inactive status and has given itself another, dynamic, IP. Does anyone know why it might be doing this and how to resolve the issue?

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    • #3869766

      DHCP server is giving itself a second IP

      by antony_k ·

      In reply to DHCP server is giving itself a second IP

      Try to disable “DHCP Client” service on your server and reboot it.

    • #3869707

      DHCP server is giving itself a second IP

      by alex ·

      In reply to DHCP server is giving itself a second IP

      Is your servers IP address in your current scope? Or have you changed your servers IP since you first created your dhcp server scope?

    • #3869652

      DHCP server is giving itself a second IP

      by netwill ·

      In reply to DHCP server is giving itself a second IP

      disable “DHCP client”

    • #3869576

      DHCP server is giving itself a second IP

      by computerdude ·

      In reply to DHCP server is giving itself a second IP

      I would exclude the Static IP from the scope instead of reserving it. Then I would manually set the IP back to the excluded address and bypass DHCP altogether. Hope this helps,

      Dave

      • #3869567

        DHCP server is giving itself a second IP

        by rob baugh ·

        In reply to DHCP server is giving itself a second IP

        OOOOPs, wrong word. The IP is excluded, not reserved. The DHCP server cannot “request” an IP from the DHCP. I have found a couple of things today. The server still responds to its excluded IP, and the second IP goes to a different MAC address. I deleted the second IP from the list of used IP’s. I do not know where the second MAC address came from, there should not be a way for another machine with the same name to log on to the network, or can a machine request an IP even if another machine has the same name?

    • #3869565

      DHCP server is giving itself a second IP

      by dross ·

      In reply to DHCP server is giving itself a second IP

      My bet would be that the DHCP service is buggy. I was running DHCP on an NT box and it began handing out the same IP addresses to multiple machines. I had to switch to a linux box as it was an emergency fix. I have not gone back. Draw back is I cannot see how many IP address are in use, and cannot reserve IP addresses. I would try removeing all of the services pertaing to DHCP, IP etc. and reinstall it.

      • #3869530

        DHCP server is giving itself a second IP

        by rob baugh ·

        In reply to DHCP server is giving itself a second IP

        My DHCP server is also the PDC, DNS, Wins. Rebuilding DHCP, and any IP related protocals is not really an option right now. As far as moving to a Linux server, definatly not an option. We semi-recently moved the DHCP service to this machine, because the original DHCP server was doing the same thing. I really don’t want to keep deleting and reinstalling the DHCP service.

        Rob

    • #3871265

      DHCP server is giving itself a second IP

      by dragon ·

      In reply to DHCP server is giving itself a second IP

      This is kind of a dumb question, but do you have 2 NIC’s in the server? If the second IP is a different MAC, that’s the only thing that would make sense.

    • #3871255

      DHCP server is giving itself a second IP

      by tbradley ·

      In reply to DHCP server is giving itself a second IP

      caller number 6 stole my thunder. I too was going to ask about a second nic. We had a gateway server with integrated NIC ( which was turned off in BIOS ), and the primary NIC was a 3com10/100. We had an extended power outage, and the bios was reset with defaults, letting the second nic bind, causing no end of problems.

      Also, any Network storage devices attached, ie Tape Drives, CD-roms, or external HD boxes?

    • #3871024

      DHCP server is giving itself a second IP

      by philthegreat ·

      In reply to DHCP server is giving itself a second IP

      You say:
      From Rob Baugh on 12/12/00 03:46 PM EST: My DHCP server is also the PDC, DNS, Wins. Rebuilding DHCP, and any IP related protocals is not really an option right now. As far as moving to a Linux server, definatly not an option. We semi-recently moved the DHCP service to this machine, because the original DHCP server was doing the same thing. I really don’t want to keep deleting and reinstalling the DHCP service.

      1) Check the MAC: does it reflect the “original” machine; not the newone?
      2) Or your server has been hacked; and this is a sym.

      I think the MAC is a way for tracing the problem. Besides, you have not given details on your setting. Does you use NT 4.0 with SP6 or win 2000; How many PDC?

      • #3868522

        DHCP server is giving itself a second IP

        by rob baugh ·

        In reply to DHCP server is giving itself a second IP

        What do you mean “sym”? I am running NT4/SP5 with W2K member servers. I will check the Mac of the “original” machine tomorrow, good call, hopefully.

    • #3871023

      DHCP server is giving itself a second IP

      by philthegreat ·

      In reply to DHCP server is giving itself a second IP

      I have found that in MS knowledge base:
      Automate Setup to Configure TCP/IP for Static Addressing Fails
      (for NT 3.5 and 3.51)

      http://support.microsoft.com/support/kb/articles/Q133/3/37.asp?LN=EN-US&SD=gn&FR=0&qry=DHCP%20does%20not%20use%20static%20IP&rnk=4&src=DHCS_MSPSS_gn_SRCH&SPR=NTS

      I hope it can help you.

    • #3871009

      DHCP server is giving itself a second IP

      by theironman ·

      In reply to DHCP server is giving itself a second IP

      I was going to ask about 2nd NIC as well, and for SP version, OS, hardware environment as well. If using SP4, up to 5 or 6. Check for roll-ups or hotfixes as well. I’ve had no probs with SP3 or SP5 with DHCP server.

      I would also concur on tracingproblem through MAC since you’ve already disabled DHCP client.

      Good Luck.

      • #3868524

        DHCP server is giving itself a second IP

        by rob baugh ·

        In reply to DHCP server is giving itself a second IP

        I am running SP5. I’ve looked on MS, but didn’t find anything, I am going to check out the site that was given above tomorrow. Thanks for the help though.

    • #3870916

      DHCP server is giving itself a second IP

      by nettek ·

      In reply to DHCP server is giving itself a second IP

      I can sense your frustration, but please be patient while I try to get your situation straight. What do you mean when you say in your original question, “DHCP…has given itself another, dynamic, IP?” This should be impossible, which leads me to believe that TCP/IP was not properly configured on the server(especially since you said you found the same situation occuring on two different machines).

      I am wondering if you have the NIC(s) on the server configured to get an IP address from a DHCPserver (in this case, itself), and then you reserved those IP addresses in DHCP manager. Because you are mentioning MAC addresses, this leads me to believe that you are viewing active leases in DHCP manager that have reservations. When you “reserve”an IP address, you are telling the DHCP server that when a particular client (in this case your DHCP server) requests an IP address, always give them this one.

      When you “exclude” IP addresses, it is usually because you have static addresses on your network that fall within your scope.

      When you go to Network Neighborhood -> Properties -> Protocols -> TCP/IP -> Properties, your DHCP server’s NIC(or NICs) should have static addresses. If these addresses are within the scope, you should exclude them in DHCP Manger -> DHCP Options -> Scope -> Excluded Addresses.

      • #3870912

        DHCP server is giving itself a second IP

        by nettek ·

        In reply to DHCP server is giving itself a second IP

        I apologize, I hadn’t read your response to Computerdude’s comment.

        Run IPCONFIG on your server and make a note of all your MAC addresses on the server. Go to DHCP manager and view active leases with reservations. See if any of the MAC addressesof the reserved addresses match any of the MAC addresses on your server. If so, remove those reservations.

      • #3868525

        DHCP server is giving itself a second IP

        by rob baugh ·

        In reply to DHCP server is giving itself a second IP

        The NIC is configured with a static “excluded” IP. I realize in the original question I used the wrong wording. Sorry. The “real” IP is in the excluded range.

    • #3868464

      DHCP server is giving itself a second IP

      by wolffster ·

      In reply to DHCP server is giving itself a second IP

      I would try a couple different things:

      1) Is there another DHCP server running somewhere? Microsoft has a tool on the NT resource kit CD called Dhcploc.exe which locates DHCP servers on a subnet. You mentioned that the DHCP was moved to another server? This may possibly be your answer. The NIC could be obtaining an IP from there from bootp.

      Don’t forget about hardware such as firewalls that may have built in DHCP. This is the first step I would take.

      If there is only one DHCP server on the subnet, make sure it is the one you are configuring.

      After that, I would attempt to use a new NIC. Make sure it is namebrand (I prefer 3Com 3C905C Series for 10/100) with the most current driver off the web. Replacing the NIC will be far less expensive than troubleshooting forever.

    • #3870566

      DHCP server is giving itself a second IP

      by tbruner ·

      In reply to DHCP server is giving itself a second IP

      1. Make sure your server is not sitting on the 1st IP address in your subnet. Remember, TCP/IP reservers this address for management. Try using the 2nd or 3 address for your NIC.

      2. Check the binding order. Go to the network icon in control panel, bindings tab and look to see if your NIC is at the top of the list for ALL BINDINGS AND PROTOCOLS. If you have a modem, added a second NIC, or NT sees anything it would regard as an adapter, it can throw the whole thing off.

      3. Exclude the first N addresses in the scope. N = 1 for each adapter and modem + 1 for RAS + (NIC address – 1st address in scope).
      EX: 2 NICS + 4 MODEMS + 1 RAS + (10.0.0.2-10.0.0.0) = 9

      4. If multiple workstations are grabbing the same IP, run winipcfg or ipconfig (depending on 9X or NT) and release both offending workstations first. Then reboot both, ONE AT A TIME.

    • #3882327

      DHCP server is giving itself a second IP

      by acgphx ·

      In reply to DHCP server is giving itself a second IP

      The reason why the DHCP Server might assign itself an IP address is if it is a RAS Server. Are you loosing any functionality?
      Are there any error messages in the event logs?

    • #3882209

      DHCP server is giving itself a second IP

      by mpdcsup ·

      In reply to DHCP server is giving itself a second IP

      Okay, a lot has been said and the question seems rather straight-forward and specific. Let’s try to break it down into possibilities. Here are the facts:

      “My DHCP server is setup with a Static IP.”

      Good, so far, we also know that there’s only one NIC and no RAS.

      “That IP is reserved for the DHCP.”

      You’ve already stated that this is an incorrect term — the (static) IP Address is *excluded* from the scope.

      “The DHCP however has set the IP to an inactive status”

      Okay, I’m having trouble here. If the address is excluded, DHCP isn’t keeping any record of this address. What do you mean?

      “…and has given itself another, dynamic, IP.”

      What is the evidence to this assertion? You stated in earlier responses that the MAC address of the offending lease is different (than the server’s) and that the server’s static address was still ping*able*.

      Are you just seeing the server’s host name in an active lease? I wonder because you asked if DHCP cared about duplicate names.

      (It doesn’t, by the way, it just takes what it’s given. NetBIOS can’t handle duplicate names and TCP/IP can’t handle duplicate IP addresses).

      “Does anyone know why it might be doing this and how to resolve the issue?”

      I’m unclear as to what the issue is. Do you have any loss of network functionality? Or, are you losing sleep because you can’t wrap your head around a questionable lease?

      If the answer is the latter, the following command may provide some relief:

      nbtstat -A http://www.xxx.yyy.zzz

      Note the capital letter, ‘A’. Substituting the IP address of the *bad* lease for http://www.xxx.yyy.zzz will produce the remote machine’s NetBIOS name registrations (logon username, NetBIOS computer name, Windows NT domain, and services that register NetBIOS names) and the MAC address. From this, you might better see where the machine with the duplicate host name is w.r.t. the NT domain.

    • #3882495

      DHCP server is giving itself a second IP

      by gbjoe ·

      In reply to DHCP server is giving itself a second IP

      I know this might sound silly and you probably have done this , but have you re-applied the service pack ?

      Hope this long shot helps.

    • #3882494

      DHCP server is giving itself a second IP

      by gbjoe ·

      In reply to DHCP server is giving itself a second IP

      I know this might sound silly and you probably have done this , but have you re-applied the service pack ?

      Hope this long shot helps.

    • #3882480

      DHCP server is giving itself a second IP

      by twest ·

      In reply to DHCP server is giving itself a second IP

      If I were you, rather than spend any more time on trying to solve this problem, I would schedule some off-hours time, and remove all networking components from this machine and re-add them. Remove all network services, protocols, and adapters, then re-boot. Then, re-add all the networking components, including the dhcp service. This time when you set up DHCP, make sure to set up the scope so that it does not include all of the IP addresses in your subnet. You should reserve some IP addresses outside of your DHCP scope for servers and networking equipment, possibly printers also.

      BTW, I do not believe this problem to be with the DHCP service. I think it is a problem with your network settings on the server or possibly the network card itself. If the above does not work, replace the network card and try again.

    • #3883123

      DHCP server is giving itself a second IP

      by gibhai ·

      In reply to DHCP server is giving itself a second IP

      my hunch is that ur dhcp server’s arp cache has entry for conflicting ip address
      arp -a to find the prob. address if present delete it using arp -d a.b.c.d
      may be this will help

    • #3761637

      DHCP server is giving itself a second IP

      by methos04 ·

      In reply to DHCP server is giving itself a second IP

      give your server a static ip address and take it out of the scope.

    • #3829909

      DHCP server is giving itself a second IP

      by daryn19 ·

      In reply to DHCP server is giving itself a second IP

      I would try to first remove and reinstall tcp/ip and remove the dhcp service from the server, do this on low network useage hours to save on downtime, i would then check the bindings of the network card to ensure that no additional bindings are there, and then reinstall the dhcp server service, and then configure the dhcp server with a static address, and make sure that there are no other dhcp servers on the etwork, reboot and see what happens.

    • #3829894

      DHCP server is giving itself a second IP

      by rob baugh ·

      In reply to DHCP server is giving itself a second IP

      This question was closed by the author

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