DHCP multiple IP helper-addresses
It is possible to configure multiple DHCP relay agents on a single interface using the ip helper-address
command like so:
interface GigabitEthernet0/1 ip address 192.168.13.3 255.255.255.0 ip helper-address 10.10.10.55 ip helper-address 20.20.20.55
In such a case, DHCPDISCOVER messages are sent to all the helper addresses configured on the interface. The client will obtain IP addressing information from whichever DHCP server responds first. It's a similar situation to having two DHCP servers on the same subnet. It's not ideal, as this can increase DHCP traffic on a network, but it is doable.