DHCP and IP Helper (DHCP Relay)

So here at my good ol’ company, we ran into an issue about a month ago where the DHCP server stopped handing out IP addresses. Come to find out the server was a Windows 2008 R2 and Windows Updates overloaded it. Nonetheless, the machines lost their IP settings as their leases expired and we lost some productivity. I had to quickly setup the 3750X switch as the new DHCP server in a hurry.

Now skip to last week, my director tasks me and the new guy, Evan, with finding a way to add redundancy to DHCP to allow fail over between servers. At Evan’s last gig, they set this up using two Windows servers with one local to the branch office and one centrally located at their data center. They would both advertise the /24 range, but the local server would exclude the last half, while the remote server would exclude the first half.