Can multiple DCs share DHCP roles for redundancy?
I have a testbed for Domain Controller integration testing with 2 subnets/sites represented.
(The subnets are interconnected and can fairly well communicate).
It's all up and running with a single DC.
Now I'm introducing a 2nd DC which will live on the other subnet/site.
The idea is twofold:
1) local subnet service
2) Dual subnet service should one of the DCs go down.
So far, so good I believe.
In the actual production environment, there is no DHCP server - but I figured I might work with DHCP a bit using the DCs.
But, I can't imagine having two DHCP servers, even on different subnets, if the subnets are interconnected as they are.
Can a single DC perform as a pair of DHCP servers - one for each subnet?
How does it know where a computer resides when interacting (re: site/subnet)?
I have my doubts but figured I'd just ask.....
(The subnets are interconnected and can fairly well communicate).
It's all up and running with a single DC.
Now I'm introducing a 2nd DC which will live on the other subnet/site.
The idea is twofold:
1) local subnet service
2) Dual subnet service should one of the DCs go down.
So far, so good I believe.
In the actual production environment, there is no DHCP server - but I figured I might work with DHCP a bit using the DCs.
But, I can't imagine having two DHCP servers, even on different subnets, if the subnets are interconnected as they are.
Can a single DC perform as a pair of DHCP servers - one for each subnet?
How does it know where a computer resides when interacting (re: site/subnet)?
I have my doubts but figured I'd just ask.....
basically, you can have multiple DHCP servers working on the same physical network, but all for the same subnet. in other words, only one subnet can be served by multiple DHCP servers (normally 2, no more than 3).
ASKER
I need to clarify all this... So, here is the network diagram.
Then, one might categorize approaches like this:
1) 2 subnets, 2 independent DHCP servers; one each, no failover or redundancy.
I think this fits using the DCs or separate DCHP servers per subnet.
2) 1 subnet, 2 independent DHCP servers; non-overlapping scopes. Provides redundancy. Not normally done(?).
This departs from the 2 subnet configuration in the diagram.
But, since this question was about using the DCs in a DHCP role. So:
2 subnets, 2 DC-based DHCP servers of some configuration (?)
Peter Hutchinson says:
I hope this helps.
Then, one might categorize approaches like this:1) 2 subnets, 2 independent DHCP servers; one each, no failover or redundancy.
I think this fits using the DCs or separate DCHP servers per subnet.
2) 1 subnet, 2 independent DHCP servers; non-overlapping scopes. Provides redundancy. Not normally done(?).
This departs from the 2 subnet configuration in the diagram.
But, since this question was about using the DCs in a DHCP role. So:
2 subnets, 2 DC-based DHCP servers of some configuration (?)
Peter Hutchinson says:
With Windows 2012 or later you can have a highly available DHCP service in a active/active or active/passive setup with replication of the scopes. So if one DHCP server goes down the other DHCP server can take over.Does this mean that single scopes are replicated or that there are multiple scopes per server that are replicated? If multiple scopes, how controlled, sensed, etc? Also, is the IP Helper Address switch function proprietary or.... ?
I hope this helps.
ASKER CERTIFIED SOLUTION
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ASKER
Thanks!
To set which DHCP server a subnet to use, you configure the IP address of the DHCP server on the network switch as a 'IP helper address'