Serving different subnets with odhcpd based on giaddr from ip helper

Installing and Using OpenWrt
1

Hi, I have multiple VLANs on an L3 switch with their own Virtual Ethernet interfaces (Cisco SVIs). I want to serve different DHCP addresses based on VLAN, but I don’t want to trunk all my VLANs to the OpenWRT router that runs odhcpd.

Instead, I can use ip helper-address on the switch to convert DHCP broadcasts (which would be stuck in their own VLAN) to unicasts sent directly to the router, and keeps track of the requesting subnet in the giaddr field . Does odhcpd support this, and if so, how can I configure it? I’m just using DHCPv4.

Thanks

2

I'm no expert in this regard. So I don't know if converting and sending the broadcasts directly to the router works at all. I would say no. Simple because its an L2/L3 (MAC/IP) issue and the usual way is trunking for this. The only way out I would see is to use its own cables for each vlan.

Beside that each Vlan interface has to have its own dhcp server declared within dhcp config.