DNS issue

Posted on 2011-05-09
Last Modified: 2012-05-11
I have a timeclock that has a static ip address of 200.236.  We were recently hit by storms and I had to replace all the network cable and the swtiches in between the timeclock and the Cisco switch.  I replaced all of them and still no network connectivity.  When I investigated further, I found out that the IP address that is being pulled is .1.37 which came from an employee who brought in a laptop from his home network, with the wireless card still active, so some how it's pulled his home network.  I have tried ipconfig /release and ipconfig /renew and nothing will reset the IP address.   How can I remove the .1.37 from the network so it will start pulling from the .200 series again?  

Question by:mwtn35
    LVL 15

    Expert Comment

    In DHCP you can setup a reservation for the .1.137 ip address and point this to the mac address of the machine. This will prevent the ip address from being leased to any other machine such as a laptop.

    Author Comment

    So by assigning the .1.37 address to that laptop, that will free up the switch to route properly and assign addresses from the .200 pool?
    LVL 15

    Expert Comment

    If you want addresses to be leased from the 200 range you need to setup the address pool from say 200-254 and then setup an exclusion for ip addresses you do not want to be leased such as your printers IPs or Server IPs etc.
    LVL 11

    Expert Comment

    As Jbond2010 mentioned this is DHCP issue not a DNS issue.  Within the network do you know what device is acting as your DHCP server?   Do you have a domain controller in this environment or is the Cisco Router/Switch set as the DHCP server?

    For example I am not sure what the exact make up of this network is but example if your time clock has a static IP address of it tells me that prior to the storm that caused the problem your network should have all had IP addresses in the 192.168.200.* range.

    What are the IP addresses of the other network devices?  If possible on a computer that is attached to the network go to a command prompt and type the following command and post the results:

    IPCONFIG /all

    Accepted Solution

    I was able to trace the issue back to a port on the Cisco Switch, apparently the user's computer "infected" the port, because it was pulling information of his laptop that directly came from his home network, so I changed network cables and plugged one into the unmanaged switch and it began assigning the proper IP addresses.  Thanks for your suggestions and assistance.

    Author Closing Comment

    Was able to trace the problem back to the switch, and there was an issue with a port on the switch, so I changed cables and was able to create a work around to fix this issue.  Thank you for your assistance

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