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  • spn


    Lately, i have been having these BAD_ADDRESS(es) on our DHCP server and i am not sure what triggers it to happen. i dont know if it is something wrong with our dhcp or else. For this problem, if i reserved an IP address for this device then it would go away for a couple of weeks then it would start again on a different machine. Let me know if you ever ran into this problem before. I really appreciate your time. TIA.

    In the Address Leases on the DHCP, the unique id for these BAD_ADDRESS(es) are showing something like this ‘6701a8c0’. it is not a valid MAC address.
    The sequence of request and update is really confusing me. The ip addresses on the BAD_ADDRESS lines are not pingable and no device in our network had those IPs during this time.

    here is a piece of the dhcp log.

    24,08/27/18,02:25:33,Database Cleanup Begin,,,,,0,6,,,,,,,,,0
    25,08/27/18,02:25:33,0 leases expired and 0 leases deleted,,,,,0,6,,,,,,,,,0
    25,08/27/18,02:25:33,0 leases expired and 0 leases deleted,,,,,0,6,,,,,,,,,0
    30,08/27/18,02:25:39,DNS Update Request,,,,,0,6, ,,,,,,,,0
    10,08/27/18,02:25:39,Assign,,CONFPC.DOMAINNAME .com,PC-MACADDRESS,,122985220,0,,,,0x4D53465420352E30,MSFT 5.0,,,,0
    32,08/27/18,02:25:39,DNS Update Successful,,,,,0 ,6,,,,,,,,,0
    30,08/27/18,02:25:39,DNS Update Request,,CONFPC,,,,0,6, ,,,,,,,,0
    13,08/27/18,02:25:39,Conflict,,BAD_ADDRESS,,,0 ,6,,,,,,,,,0
    32,08/27/18,02:25:39,DNS Update Successful,,,,,0 ,6,,,,,,,,,0
    30,08/27/18,02:25:52,DNS Update Request,,,,,0,6, ,,,,,,,,0
    10,08/27/18,02:25:52,Assign,,CONFPC.DOMAINNAME .com,PC-MACADDRESS,,641243928,0,,,,0x4D53465420352E30,MSFT 5.0,,,,0
    32,08/27/18,02:25:53,DNS Update Successful,,,,,0 ,6,,,,,,,,,0
    30,08/27/18,02:26:09,DNS Update Request,,,,,0,6, ,,,,,,,,0
    13,08/27/18,02:26:09,Conflict,,BAD_ADDRESS,,,0 ,6,,,,,,,,,0
    32,08/27/18,02:26:09,DNS Update Successful,,,,,0 ,6,,,,,,,,,0
    30,08/27/18,02:26:19,DNS Update Request,,,,,0,6, ,,,,,,,,0
    10,08/27/18,02:26:19,Assign,,CONFPC.DOMAINNAME .com,PC-MACADDRESS,,2953808784,0,,,,0x4D53465420352E30,MSF T 5.0,,,,0
    32,08/27/18,02:26:20,DNS Update Successful,,,,,0 ,6,,,,,,,,,0
    24,08/27/18,02:30:35,Database Cleanup Begin,,,,,0,6,,,,,,,,,0
    25,08/27/18,02:30:35,0 leases expired and 0 leases deleted,,,,,0,6,,,,,,,,,0

    DOMAINNAME: our network domain name
    The above sequence is from one pc (CONFPC).
    OS: Windows Server 2012 R2

    Thanks again.


    It looks as though the address that is ‘bad’ already exists on your network. Have you checked wireless access points, iDRAC (or other management addresses) etc?

    Also, check that your DHCP records tally with your Forward and Reverse zone records. I have seen this where PTR’s or A records have not been claimed back by the DHCP server, and duplicate records have existed.

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