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DHCP 80/20 Backup DHCP server setup

bergquistcompany
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We are setting a secondary server up with DHCP to act as a backup DHCP server with 20% of the IPs.  I understand to install DHCP and setup the scope for the selected range, excluding the 80% the primary server will give.  However I was reading to use superscopes for multiple DHCP servers on each subnet in a LAN environment.  Do I have to change something on the current DHCP server outside of adding the exclsions to make it superscope?  After activating the backup DHCP server (20%) is there something I need to do here as well?  
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Brian BEE Topic Advisor, Independant Technology Professional

Commented:
The backup server will still need to have enough capacity to handle 100% of the leases, otherwise it won't be able to accept fail over if the primary goes down.

Author

Commented:
I understand that but for now I want to setup
10.1.2.1-10.1.2.200
ex: 10.1.2.161-10.1.2.200

Server 2
10.1.2.1-10.1.2.200
ex: 10.1.2.1-10.1.2.160

However it said something about them being on the same LAN and broadcasting so to use superscopes to avoid using more than one DHCP in the same subnet.  I'm wondering from people who have set this up, if I install the second server as above, how do I setup superscope and is it necessary from those using 80/20
Brian BEE Topic Advisor, Independant Technology Professional

Commented:
You are correct in your original statement that you need to use superscopes for multiple subnets. However you are not using multiple subnets it both servers are serving in the range 10.1.2.0/24 (i.e. both on the same subnet).

If you had DHCP on two separate subnets, i.e. 10.1.2.0/24 and 10.1.3.0/24 then you would need a superscope.

Author

Commented:
Ok just to clarify, we have 10.1.2.1-10.1.2.200 on a server assigning DHCP at a branch office.
I have a secondary secondary machine I will be putting DHCP on at that same site as the 20%.
The corporate location assigns it's own DHCP 10.2.2.1-10.2.2.200.
Both have 255.255.0.0 subnets
Given this can I:
1. Leave the 10.1.2.1-10.1.2.200 on the branch office server and the only modification to it would be adding the exclusion.
2. Install and configure DHCP on the secondary server at the branch office as above.
3. No superscope?
EE Topic Advisor, Independant Technology Professional
Commented:
All yes. That is exactly the way I have done it in the offices I have set up.

Author

Commented:
Very helpful and detailed