DHCP failover on another DC

[chekmate1984]

Hi all

 

 

Our DC1 that has DHCP has tendency to go down often - we have plans to upgrade it but wont be till easter due to budgets

 

Can we install DHCP on DC2 as well so can work as failover if DC1 goes down?

 

I was under assumption you can but it will have to be another subnet but not sure if we can have copy of DHCP on another server

 

thanks

[Norphy]

Windows DHCP has had the ability to balance DHCP scopes across multiple servers and failover since Windows 2012 R2 I think. You don't need to do the 80/20 split thing any more.

 

https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2012-r2-and-2012/dn338978(v=ws.11)

[Davit2005]

80/20 split scope between the 2 DCs is my normal method depending on lease time. You want the lease time to cover the time to bring the other DHCP back into service. You don't necessarily have to use the split scope as long as the DHCP IP addresses ech server gives out do not overlap but using it makes it a lot easier.

 

I know new versions of Windows you can do DHCP failover but I think the 80/20 is good enough if you have enough room for maneuver in the IP ranges and you don't have to worry about setting up clusters of anything. Did try DHCP failover myself many years back on server 2012r2 but did not have much success might of improved now.

Edited November 3, 2022 by Davit2005

[DavR]

+1 for DHCP failover.

 

We have it on Server 2022, the same scope across two DCs. Once it's set up, it's pretty straightforward, and deals with the loss of one DC just fine.

 

Under the hood, it essentially behaves like a split scope, doing a 50/50 split of the address pool, but keeping a record of the whole scope on both boxes. If one partner is down for long enough, the other just assume full control.