Cisco 3550 switch as DHCP relay agent with Windows 2000 server dhcp server
Posted on 2004-08-26
10.4.0.0/16 ------------CISCO 3550 SWITCH --------10.1.0.0/16---------------FW-------->Internet
| main DHCP server
test DHCP server
I have a Cisco 3550 switch sitting on a 10.1.0.0 network. The switch has two VLANs on it , 10.4.0.0 and 10.3.0.0. I'm trying to get clients on these VLANs to obtain their IP addresses form the DHCP server on the 10.1.0.0/16 network.
The switch acts as a router for inter-vlan traffic.
There are no ACLs between the VLANs.
The Default gateway for the Switch is the FW and the FW routes back any traffic destined for the 10.4.0.0 / 10.3.0.0 networks that comes from the 10.1.0.0 network to the switch IP address.
All this works fine.
The main DHCP server (a windows 2000 type) has three scopes on it, one for each of the subnets. I belive the switch should have a dhcp relay agent on it by default. However none of the clients on either of the VLANs can find the main DHCP server, clients on the 10.1.0.0 network have no such problem.
As a test I configured a test DHCP server on the 10.3.0.0 VLAN. Again, although clients on the same VLAN can get DHCP IPs. Clients on the 10.4.0.0 VLAN cannot.
Do I need to configure the Switch in to forward DHCP requests? Or is my proposed scenario impossible?
Many thanks for any help given.