You would add the helper statement under either the routed interface or VE. This is generally done at the default gateway for the respective vlan. An example might look something like this:
interface ve 10
ip helper-address 1 192.168.20.1
192.168.20.1 would be a DHCP server in a different subnet.
I currently have 18 DHCP scopes setup on a Windows DHCP server. The only configuration required on the switches is on the Core switch that is doing the VLAN routing. That is the switch that has the interfaces on it that is the default gateway for clients. On each VLAN interface, you have to configure an IP Helper Address that is the IP address of the DHCP server. Once this is setup your VLANs will get directed to the DHCP server and get a correct IP address for the scope associated with that VLAN.
Syntax: ip helper-address num ip-addr
The num variable specifies the helper address number and can be from 1 through 16.
The ip-addr variable specifies the server IP address or the subnet directed broadcast address of the IP subnet the server is in.
Thanks for the reply.
in terms of this, we have around 20 odd scopes specified on the windows dhcp. how would i get around selecting a subnet to be used?
say if vlan 120 is for one area and has the scope 192.168.120.0 how would i instruct this to be sent to the connecting switch?
and the address of the controlling server is 192.168.14.11