Dell PowerEdge M420 Reference Manual page 908

User Guidelines
This command can be invoked multiple times on routing interface, either to
specify multiple server addresses for a given port number or to specify
multiple port numbers handled by a specific server.
The command no ip helper-address with no arguments clears all helper
addresses on the interface.
Example
To relay DHCP packets received on vlan 5 to two DHCP
servers, 192.168.10.1 and 192.168.20.1, use the
following commands:
console#config
console(config)#interface vlan 5
console(config-if-vlan5)#ip helper-address
192.168.10.1 dhcp
console(config-if-vlan5)#ip helper-address
192.168.20.1 dhcp
To relay both DHCP and DNS packets to 192.168.30.1, use the following
commands:
console#config
console(config)#interface vlan 5
console(config-if-vlan5)#ip helper-address
192.168.30.1 dhcp
console(config-if-vlan5)#ip helper-address
192.168.30.1 dns
This command takes precedence over an ip helper-
address command given in global configuration mode.
With the following configuration, the relay agent
relays DHCP packets received on any interface other
than vlan 5 and vlan 6 to 192.168.40.1, relays DHCP
908
IP Helper/DHCP Relay Commands