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DHCP Active-Active loadbalncing across datacenter RRS feed

  • Question

  • Hello,

    My understanding of the DHCP locabalancing is that both DHCP servers in the loadbalancing pair should be on the same subnet.

    Would it be possible to do loadbalaned DHCP servers accross multiple datacenters, where each server is on different subnet.

    Thanks,

    mohjav.


    • Edited by mohjav Monday, July 8, 2019 5:41 PM
    Monday, July 8, 2019 5:41 PM

All replies

  • Hi,

    Yes, DHCP failover is used for the same subnet, so it is not possible to configure load balancing between different subnets.

    Please refer to the link below:

    https://docs.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2012-R2-and-2012/dn338976(v=ws.11)

    Best regards,

    Travis


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    Tuesday, July 9, 2019 6:30 AM
    Moderator
  • Thanks Travis. Are you aware of any DHCP product that is capable of doing active active loadbalancing across  different subsets?
    Wednesday, July 10, 2019 7:41 AM
  • Hi,

    Sorry, I don't think that there is a DHCP product that supports active active loadbalancing across different subsets.

    Maybe you can consult third party DHCP product support.

    Best regards,

    Travis


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    Wednesday, July 10, 2019 9:32 AM
    Moderator
  • Hi,

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

    Please let us know if you would like further assistance.

    Best Regards,

    Travis


    Please remember to mark the replies as an answers if they help.
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    Friday, July 12, 2019 6:25 AM
    Moderator
  • Hi Travis,

    Researched few products who claimed that could run DHCP active-active cross datacenter, but were expensive.

    So i decided to see if windows DHCP would allow this configuration at all.

    To my surprise i was able to install two dhcp servers in two different subnets.

    • DHCP1 (10.1.1.10/24)
    • DHCP2 (10.2.2.10/24)
    • Created a scope on DHCP1 (192.168.0.0/24)
    • Create an Active-Active failover loadbalancing across the two

    I used windows 2019 and I can confirm the configuration is possible. But makes me wonder why this type of config is not documented anywhere. I havent actually tested with live traffic yet. Will try it next week.

    Thinking further, I thought of one possible issue. I am using the DHCP server to register DNS records as well. This means that each DHCP server in the cluster will register DNS records to the local DNS server in each site. Eg: UK DHCP register DNS records to UK DNS server and US DHCP register DNS records to US DNS server. So 50% of the clients in UK will have to wait for the DNS record to replicate cross site for them have fully functional DNS records.

    


    • Edited by mohjav Friday, July 26, 2019 9:23 PM
    Friday, July 26, 2019 8:01 PM
  • Hi,

    Sorry, I misunderstood what you mean.

    Yes, the DHCP failover architecture above is OK.

    However, there are some requirements when you deploy failover, please refer to the link below:

    https://docs.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2012-R2-and-2012/dn338982(v=ws.11)  

    https://docs.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2012-R2-and-2012/dn338979(v=ws.11) 

    Best regards,

    Travis


    Please remember to mark the replies as an answers if they help.
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    Monday, July 29, 2019 6:53 AM
    Moderator
  • Hi,

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

    Please let us know if you would like further assistance.

    Best Regards,

    Travis


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

    Tuesday, July 30, 2019 2:28 AM
    Moderator