Multiple DHCP servers on a single VLAN- HP 5406zl Multiple IP Helper-Address

Have you ever wanted to add a second DHCP server in case the first went offline? It's a lot simpler then you think. I recently set this up for our main office, as with our aging VM hosts I did not want

to take everyone offline if we lost one of the hosts. For this we need two servers- I already had two Server 2008r2 VM's setup: AD1 and AD2. They were already configuered for split DNS. Simply add the DHCP role to the second server and setup your scopes. It is important to A) Split your scopes- they can not overlap, and B) Split your DNS- If AD1 goes offline, you loose DHCP and DNS. See the example below.

 

Example:

 

AD1-DHCP: 10.10.10.3 

         Scope: 10.10.10.50-149

         DNS1: 10.10.10.3

         DNS2: 10.10.10.4

 

AD2-DHCP: 10.10.10.4

         Scope: 10.10.10.150-250

         DNS1: 10.10.10.4

         DNS2: 10.10.10.3

 

On our HP switches, I had to configure a second IP Helper-Address:

 



 

Before:

 

Command:

Result



 



As with most HP switch changes, make sure to do a WR MEM and RESET- to apply your changes.
Enjoy!