I've got the following subnets setup for the VLAN's on my network.

The DHCP server is on the subnet and works fine on it's own physical subnet, but not machines on the other subnets can get an IP.

Each subnet is connected to a 3com 5500 layer 3 switch. The switch is setup to forward all DHCP requests to the DHCP IP address, which is

Is there anything special that I need to do on the DHCP server for this to work? The switch is setup exactly how it shows on the 3com knowledge base so I figured it's something to do witht he DHCP server config.