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DHCP Hot-Standby reserve percentage-Will laptops taken home need reserved addresses next day? RRS feed

  • Question

  • I have a 2012R2 domain and trying to decide what reserve percentages to keep for the DHCP Hot-Standby server, as we have a few scopes with heavy utilization.  I think I read that by default if a computer reboots, it should come back up and send out a DHCPrequest to the last DHCP server and not use a new IP.  So for that, we would be alright in the event of a 24-48 hour failure, with a smaller reserve percentage of like 10% in reserve.  The concern is people who have laptops, and take them home and power them up off the network.  When those devices come in the next morning with the be sending out a DHCPrequest for the IP address it used the previous day? or will it send out a DHCPoffer for a new address and start pulling from the reserved addresses of the Hot-Standby server(in the event of a failure?  


    Dave






    • Edited by DaveBryan37 Wednesday, May 17, 2017 6:51 PM
    Wednesday, May 17, 2017 6:46 PM

Answers

  • Hi DaveBryan37

    >> The concern is people who have laptops, and take them home and power them up off the network.

    Client will reacquire IP address by broadcasting a DHCP Discover message.

    >> start pulling from the reserved addresses of the Hot-Standby server

    Yes, if you have configured the reserved address.

    Best Regards,

    Candy


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    • Marked as answer by DaveBryan37 Monday, May 22, 2017 3:43 PM
    Thursday, May 18, 2017 3:16 AM

All replies

  • Hi DaveBryan37

    >> The concern is people who have laptops, and take them home and power them up off the network.

    Client will reacquire IP address by broadcasting a DHCP Discover message.

    >> start pulling from the reserved addresses of the Hot-Standby server

    Yes, if you have configured the reserved address.

    Best Regards,

    Candy


    Please remember to mark the replies as answers if they help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    • Marked as answer by DaveBryan37 Monday, May 22, 2017 3:43 PM
    Thursday, May 18, 2017 3:16 AM
  • Hi Dave,

    As far as I understand your question, the client just sends a request to DHCP server for an IP address (it cannot send a request for specific IP address). It is the DHCP server who assigns an IP address to client (may be specific if an IP is already reserved for the client).

    In the event of DHCP failure, if your laptop user sends a request for an IP address, partner DHCP server will lease out an IP address from those 10% of IP addresses.

    Thank you, 

    Saturday, May 20, 2017 10:29 AM
  • Hi DaveBryan37,

    Just checking in to see if the information provided was helpful.

    Please let us know if you would like further assistance.

    Best Regards,

    Candy


    Please remember to mark the replies as answers if they help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Monday, May 22, 2017 1:38 AM
  • Thanks Candy - I was thinking that is how it would work, but was not 100%

    Dave


    Monday, May 22, 2017 3:45 PM