Dell PowerConnect M6348 Cli Reference Manual page 617

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
and DNS packets received on vlan 5 to 192.168.40.2, relays SNMP
traps (port 162) received on interface vlan 6 to 192.168.23.1, and
drops DHCP packets received on vlan 6:
console#config
console(config)#ip helper-address 192.168.40.1 dhcp
console(config)#interface vlan 5
console(config-if-vlan5)#ip helper-address 192.168.40.2 dhcp
console(config-if-vlan5)#ip helper-address 192.168.40.2 domain
console(config-if-vlan5)#exit
console(config)#interface 2/6
console(config-if-vlan6)#ip helper-address 192.168.23.1 162
console(config-if-vlan6)#ip helper-address discard dhcp
ip helper enable
Use the ip helper enable command to enable relay of UDP packets. To disable relay of all UDP
packets, use the "no" form of this command.
Syntax
ip helper enable
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