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Ping to local nic ip responds even if network cable is disconnected

    Question

  • OS: Windows Server 2008 Standard Service Pack 1

    I have a PC with an ethernet card (IP:10.0.0.1).
    When i run a PING from this PC to its own IP address (PING 10.0.0.1) it gives me a response even if the network cable is disconnected from the NIC.
    In my other PC, running Windows XP, this is not the case: when i disconnect the network cable from the NIC the PING stops responding.
    I need this behavior to be like in Windows XP.

    Thank you.
    Thursday, March 04, 2010 2:56 PM

All replies

  • I'm not completly shure about it: But I think, that it has something to do with the network adapter itself. If it does an automatic hardware-loopback, if no cable is connected, it will respond to a PING...

    That means, it should not have anything to do with the OS itself...
    Thursday, March 04, 2010 3:04 PM
  • Thanks cal77 for your reply.

    Unfortunatley, this behavior is observed on two different machines
    running Windows Server 2008, and on all four network adapters:

    PC 1:

    NIC1: VIA Rhine II (onboard) - 10.1.0.1/255.0.0.0
    NIC2: Realtek RTL8139 (PCI) - 10.0.0.1/255.0.0.0

    PC 2:

    NIC1: SiS 900 (onboard) - 10.1.0.2/255.0.0.0
    NIC2: Realtek RTL8139 (PCI) - 10.0.0.2/255.0.0.0

    The Windows network configuration is mostly the default, only the static IP/Mascs where configured.

    Also, "Network Load Balancing (NLB)" was installed and configured over the two PCI NICs.
    Thursday, March 04, 2010 6:29 PM
  • I am not sure but still I am sharing my gut feeling below. 

    Ideally it should not respond to 100.0.0.1 with default settings. If MAC/PHY loopback bit is set in loopback register (or its equivalent) then this will loop back data. But this is not default setting.

    If you are looking for just loopback from IP stack use 127.0.0.1, or know how to set MAC/PHY Loopback. 
    Vishal Jain, MSFT
    Friday, March 05, 2010 8:44 AM
  • Thanks Vishal_Jain for your reply.

    The NICs are with default setting.

    I need that when I make a ping to local NIC IP address, it don't responds if UTP cable is disconnected.
    Friday, March 05, 2010 11:26 AM
  • Hi,

    any update on the issue ?

    Wednesday, March 24, 2010 6:55 AM
    Moderator
  • Hi,

    I could not solve this problem.

    Saturday, April 03, 2010 3:07 AM
  • Run your ping from a remote node instead of local.  Pinging locally tests the software stack, not the hardware.
    Friday, April 09, 2010 8:03 PM