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WakeOnLan aware network cards causing IPAddress conflict RRS feed

  • Question

  • Hi,

    We have a lot of computers using Realtek RTL8111DP network cards. This card is compatible with WOL/DASH . When computer is power off, the network card start an service that keeps listening on port 22. Yes it keep an active IP Address active, reponding to ICMP requests too.

    So, when the computer is on, I can see on Leases table the IpAddress assigned to a  regular hostname. When the computer is powered off, sometimes the network card send a request do DHCP with hostname  'dash'.

    If a computer is off  and your dhcp lease expires, dhcp server will design this IPAddress to another machine, but the network is still using the same IP, so this is causing many  conflicts on network.  If I enable the Conflict Detection,  dhcp server register leases with BAD_ADDRESS to show this conflicts.

    Anyone has had a similar problem ? What was the solution to fix/Workaround it ?

    Thank´s

    Lisandro

    Thursday, June 9, 2016 9:31 PM

Answers

  • Hi,

    Computers Do Not Wake Up Because They Have Changed Their IP Address Since the Last Hardware Inventory Cycle

    When the site server uses unicast as the wake-up transmission method, it sends the wake-up packet to the target computer's last known IP address (from hardware inventory). If the target computer no longer has the same IP address, it will not receive the wake-up packets.

    When the site server uses subnet-directed broadcast as the wake-up transmission method, it sends the wake-up packet to the target computer's last known IP subnet address (from hardware inventory). If the target computer no longer has the same subnet address (for example, it is a client that frequently roams in the Configuration Manager hierarchy), it will not receive the wake-up packets.

    Solution

    Increasing the DHCP lease time and configuring the hardware inventory schedule to run more frequently can help to reduce the likelihood of sending wake-up packets to out-of-date addresses.

    Additionally, if computers frequently change IP addresses but keep the same subnet address, selecting subnet-directed broadcast rather than unicast as the transmission method will prove more effective in waking up computers.

    For more information, see the following topics:

    REF:Troubleshooting Wake On LAN Issues

    https://technet.microsoft.com/en-us/library/bb932199.aspx?f=255&MSPPError=-2147217396

    ________________________________________
    Best Regards,
    Cartman
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    Friday, June 10, 2016 2:57 AM