IP Helper Sanity Check

Hi All,

We have a Windows DHCP Server setup in Active \ Hot-Standby

DHCP Server 1: 192.168.1.1 - Active

DHCP Server 2: 192.168.2.1 - Standby

I've got helpers configured like so on the interface

ip helper address 192.168.1.1

ip helper address 192.168.2.1

The Standby server won't respond to DHCP Discover packets unless it is the active server, and from reading Cisco's documentation when two helpers are configured on the interface it will send the discover packet to both addresses and the server that responds first wins.

I performed a test last night and forced the fail-over to the secondary server I do see a failure for name registration, but I couldn't see a lease coming through.

I am just wanting to confirm that there would be nothing that from the network side that would prevent it from getting an address.

• No firewall in between
• Confirmed the client can ping 192.168.2.1

To force the fail over I did the following:

• stopped the service on the primary
• Told the secondary, the primary was down
• The client lead time is set to one hour
• No auto state cutover
• Did a release and renew on the client
• Viewed lease through the console.