I'm configuring another DHCP server 2012r2 as a Standby server in case my primary DHCP server fails. On my CISCO routers, I have the IP helper pointing to my primary DHCP server. Will I need to add another IP helper address to all my routers pointing to the failover DHCP server in the case my primary goes down? Or will it just sense there is no heartbeat on the primary DHCP server and start pulling from the Failover DHCP server? Please advise... Thx!