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Is it possible to create a DHCP Failover Cluster between a Linux(Ubuntu) based server and a Windows Server 2012R2 based server. My idea was to include a new data into the dhcp.conf data to exclude a specific part of the area.

E.g. a company has a big network 10.10.10.0/20 with nearly 4000 clients.
As a result my network goes from 10.10.0.0 to 10.10.15.255.
Now I want my Linux- based DHCP Server to exclude the area between
- 10.10.0.0 - 10.10.4.255
- 10.10.10.0 - 10.10.10.255
And my Windows Server 2012R2 should be responsible for this part.

I revently read about a failover cluster between 2 Linux- based DHCP Server and between 2 Windows- based DHCP- Server but I did not found a source for a mix between 'em.

Thank you for your time.

Greetings

// EDIT: Of course I meant to split a scope like 10.10.10.0/20.
Only the parts 10.10.0.0 - 10.10.4.255
and 10.10.10.0 - 10.10.10.255
should be processed by the Windows-based DHCP- Server.

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  • Not 100% sure it's possible. Sep 3, 2014 at 13:38
  • Why do you want to do split scope rather than a real HA solution? What is the larger problem that you're trying to solve here. This looks like an XY problem in the making.
    – MDMarra
    Sep 3, 2014 at 14:16
  • Well... My Ubuntu DHCP- Server is responsible for that specific IP range. Because I want to substitude the Ubuntu DHCP- Server with a Windows Server2012R2 I need to delegate some parts of the IP area to the Windows DHCP- Server. I can't eliminate the Ubuntu-based DHCP Server at once, because there are other important services which I can't transfer, yet. Is it possibile to tell the Ubuntu DHCP Server that there's a Windows 2012R2 based DHCP Server who should be responsible for some parts of the IP area? Sep 3, 2014 at 14:32
  • Why don't you just lower the lease time on the Ubuntu server to something very short, like 1 hour, configure the scope(s) on the Windows box, but don't enable them, plan some downtime over the weekend, turn off dhcpd on the Ubuntu and enable the pre-staged scoped on the Windows box? Within an hour, everything will be transitioned to the Windows box and you can keep the Ubuntu box in service without dhcpd turned on. I think you are overthinking this one.
    – MDMarra
    Sep 3, 2014 at 16:24
  • The requirement is to switch those parts of the scope at first. The other stuff will be perfomed in a few months. Sep 4, 2014 at 7:13

3 Answers 3

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Server 2012 R2 comes with a DHCP failover built-in so you don't need to use a failover cluster or do split scoping. As far as I know, this isn't possible with a mixed Linux/Windows DHCP setup.

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  • That might help, too. At least for now. <br/> Could you recommend me a website with a tutorial ? Thanks you ! Sep 3, 2014 at 13:36
  • I blogged about this: mdmarra.com/2013/07/configuring-ha-dhcp-on-windows-server.html That link will get you a base HA install. There are, of course, other options to configure, but that's a start.
    – MDMarra
    Sep 3, 2014 at 13:40
  • 1
    One thing to note is that "Split scope" is not the same as "DHCP failover". You can manually split scope whatever you want. That just means that there are range exclusions defined on DHCP servers that independently service the same scope. DHCP failover means that leases are replicated, so that any DHCP server in the failover group knows about all leases and can service all addresses in the scope (which is far superior to split scope)
    – MDMarra
    Sep 3, 2014 at 13:49
  • I am sorry for my mistake. Of course I meant to split a scope. Sep 3, 2014 at 13:55
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Unless you are willing to put your hands in ISC DHCP's core code and develop a DLL for Microsoft's, that is pretty much impossible I'd say. Both servers run with different representation of leases / statics / scopes and so on. Or you could do a 80%/20% configuration style for one server covering 80% of a range and the other the 20% left, but that is not a real DHCP failover.

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  • Y'know.. Assuming you didn't mind all the leases expiring, and everything having to find a new server.. it would be possible (but ugly as sin) to have both servers covering 100% of the range, set the lease to something teeny, and use some virtual IP technology to switch them over. So long as they're not both online at the same time. Sep 3, 2014 at 13:41
  • Yes that would be possible, but the fact that one of the two servers is not online is not really a failover (well, not an automatic one at least).
    – NaeiKinDus
    Sep 3, 2014 at 13:42
  • I need both of them online. The Linux- based DHCP- server should be removed - step by step. At fist I need to transfer some parts of the area from the Linux- based DHCP- Server to the Windows- based DHCP- Server. Yes, this procedure is quite uncomfortable and unusual. But that's how it should be elapsed. Sep 3, 2014 at 13:53
  • @mushroomer in that case there is absolutely no issue doing what you want to do; as stated by MDMarra you need to create a splitscope configuration, both servers excluding one another on specific ranges.
    – NaeiKinDus
    Sep 3, 2014 at 14:36
  • I found a solution based on a filtering technique. I created the same scope on the ubuntu server and told him to manage only the clients with a specific MAC address. Then I put them on the blacklist on the windows dhcp server and created a whitelist with specific Mac- adresses. Now nobody will give any unknown client an IP- address and they don't bother each other. They only answer DHCPDISCOVER messages with their known MAC- addresses. Thanks for your help ! :) Sep 5, 2014 at 8:39
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I don't think that what you are asking is possible under your currrent configuration.

I can see a possibility of temporarily sub-netting the network space you have into two groups, 1. UNIX/Linux hosts and 2. Windows hosts. Thus you could have two DHCP servers, one for each sub-network. When you are finished with your transition, you can then recombine the networks back into the original space and have only one DHCP server.

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