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DHCP failover 2012 R2 -> 2016 RRS feed

  • Question

  • Good morning everybody.

    I actually have DHCP failover between two Windows Server 2012 R2 in one site. It working perfectly since 2 years.

    1. Is it possible to configure DHCP failover between Windows Server 2012 R2 and Windows Server 2016 ?

    2. If I have on DHCP in one site and another DHCP in a remote site with DHCP failover, if one server crash, no problem the second will take the lease. But my question is : If the network link goes down between my primary and seconday site, what happen ? The primary site will use it's own DHCP and the secondary site it's own DHCP ? When the network link goes up, what happen ?

    Thank you so much for your help.

    Best regards

    Wednesday, October 11, 2017 8:31 AM

Answers

  • Hi,

    >>1. Is it possible to configure DHCP failover between Windows Server 2012 R2 and Windows Server 2016 ?

    Yes,please note the points below.

    1. Both DHCP servers in a DHCP failover relationship must be running Windows Server 2012 or a later operating system.
    2. Both computers participating in a DHCP failover relationship must have the DHCP Server role installed and running.
    3. Use a static IP address on all DHCP server network interfaces.
    4. At least one IPv4 DHCP scope must be configured on the primary DHCP server.
    5. DHCP failover supports DHCPv4 scopes only. DHCPv6 scopes cannot be failover-enabled.
    6. You cannot configure DHCP failover on a DHCP scope to include more than two DHCP servers.

     

    >>2. If I have on DHCP in one site and another DHCP in a remote site with DHCP failover, if one server crash, no problem the second will take the lease. But my question is : If the network link goes down between my primary and seconday site, what happen ? The primary site will use it's own DHCP and the secondary site it's own DHCP ? When the network link goes up, what happen ?

    In load balancing mode, when a DHCP server loses contact with its failover partner it will begin granting leases to all DHCP clients. If it receives a lease renewal request from a DHCP client that is assigned to its failover partner, it will temporarily renew the same IP address lease for the duration of the MCLT. If it receives a request from a client that was not previously assigned a lease, it will grant a new lease from its free IP address pool until this is exhausted, and then it will begin using the free IP address pool of its failover partner. If the DHCP server enters a partner down state, it will wait for the MCLT duration and then assume responsibility for 100% of the IP address pool.

    More information about DHCP failover,  please refer to the following article:

    https://technet.microsoft.com/en-us/library/dn338976(v=ws.11).aspx

    Best Regards,

    Frank


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    Friday, October 13, 2017 2:17 AM

All replies

  • Hi,

    Thank you for your question. I am trying to involve someone familiar with this topic to further look at this issue. There might be some time delay. Appreciate your patience.

    Thank you for your understanding and support.

    Best Regards,

    Frank


    Please remember to mark the replies as answers if they help and unmark them if they provide no help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Thursday, October 12, 2017 10:15 AM
  • Ok thank you very much for your help.

    Best regards

    Thursday, October 12, 2017 11:36 AM
  • Hi,

    >>1. Is it possible to configure DHCP failover between Windows Server 2012 R2 and Windows Server 2016 ?

    Yes,please note the points below.

    1. Both DHCP servers in a DHCP failover relationship must be running Windows Server 2012 or a later operating system.
    2. Both computers participating in a DHCP failover relationship must have the DHCP Server role installed and running.
    3. Use a static IP address on all DHCP server network interfaces.
    4. At least one IPv4 DHCP scope must be configured on the primary DHCP server.
    5. DHCP failover supports DHCPv4 scopes only. DHCPv6 scopes cannot be failover-enabled.
    6. You cannot configure DHCP failover on a DHCP scope to include more than two DHCP servers.

     

    >>2. If I have on DHCP in one site and another DHCP in a remote site with DHCP failover, if one server crash, no problem the second will take the lease. But my question is : If the network link goes down between my primary and seconday site, what happen ? The primary site will use it's own DHCP and the secondary site it's own DHCP ? When the network link goes up, what happen ?

    In load balancing mode, when a DHCP server loses contact with its failover partner it will begin granting leases to all DHCP clients. If it receives a lease renewal request from a DHCP client that is assigned to its failover partner, it will temporarily renew the same IP address lease for the duration of the MCLT. If it receives a request from a client that was not previously assigned a lease, it will grant a new lease from its free IP address pool until this is exhausted, and then it will begin using the free IP address pool of its failover partner. If the DHCP server enters a partner down state, it will wait for the MCLT duration and then assume responsibility for 100% of the IP address pool.

    More information about DHCP failover,  please refer to the following article:

    https://technet.microsoft.com/en-us/library/dn338976(v=ws.11).aspx

    Best Regards,

    Frank


    Please remember to mark the replies as answers if they help and unmark them if they provide no help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Friday, October 13, 2017 2:17 AM
  • Hi,
    Just checking in to see if the information provided was helpful. Please let us know if you would like further assistance.

    Best Regards,

    Frank

    Please remember to mark the replies as answers if they help and unmark them if they provide no help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Monday, October 16, 2017 9:37 AM
  • Hi,

    Was your issue resolved? 

    If you resolved it using our solution, please "mark it as answer" to help other community members find the helpful reply quickly.
    If you resolve it using your own solution, please share your experience and solution here. It will be very beneficial for other community members who have similar questions.
    If no, please reply and tell us the current situation in order to provide further help.

    Best Regards,
    Frank

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    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Thursday, October 19, 2017 9:14 AM
  • Good morning,

    Thank you very much for all your explanation.
    Sorry for the late answer, I was on holidays :-)

    Good news that I can do failover between my 2012 R2 and 2016 DHCP server :-)

    In my case, I use DHCP load balance mode.

    As you explain, it will work great in my case if the link between my two site when down, it's right ?

    Thank you very much for all your help, very appreciate.


    Wednesday, November 1, 2017 9:21 AM
  • Hi,

    Your understanding correctly.

    Please "mark it as answer" to help other community members find the helpful reply quickly.

    Best Regards,
    Frank


    Please remember to mark the replies as answers if they help and unmark them if they provide no help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Wednesday, November 1, 2017 9:26 AM
  • Thank you very much !

    Have a nice day

    Thursday, November 2, 2017 10:18 AM
  • Actually no, it is not always possible.

    I am trying to do exactly this: 2016 server DHCP (primary) to a 2012R2 DHCP (potentially the failover). 

    I used this article in order to try it out:

     https://blogs.technet.microsoft.com/teamdhcp/2012/09/10/migrating-existing-dhcp-server-deployment-to-windows-server-2012-dhcp-failover/

    However I get the following:

    Message: The DHCP server version 6.3 is not compatible with the file version 10.0. 

    So It just means that from a Primary 2012R2 server you can potentially export and create the failover toward a 2016 server but the reverse is not possible due to settings or format of the database.

    Unless I missed something, let me know.

    Friday, April 6, 2018 9:35 PM