DHCP Relay with seperate interface

Question

Hi,

Have used DHCP Relay before with success (in switches), but this configuration seems to get me in trouble, maybe the UTM does not support this, but I hope you guys can shed some light into this [:)]

Network is connected like this:

LAN:
Network 10.30.32.0/21
SERVER 10.30.32.5 (WINDOWS 2008 AS DC AND DNS,DHCP)
UTM 10.30.32.1

On the LAN are also Sophos accesspoints connected.

SSID: WORK (AP'S BRIDGE TO LAN)

SSID: GUESTS (AP'S USE SEPERATE INTERFACE)

Seperate interface WLAN0:
Network: 10.20.32.0/21

DHCP RELAY ENABLED:
SERVER TO RELAY TO IS 10.30.32.5
INTERFACE TO RELAY FROM IS: SEPERATE INTERFACE (WLAN0)

Server has two dhcp scopes, on for LAN range and one for the WLAN0 interface IP range.

Problem is that when clients connect to the guest network, they get wifi access, but no DHCP traffic is transmitted.
if I enable the DHCP server in UTM on the WLAN0 interface, everything works.

Doesn't the DHCP RELAY function in the UTM work as a "DHCP HELPER" as known from ex. Cisco switches??

If not, is this config possible anyway?

UTM is using 9.209 but the issue is the same with 9.302

This thread was automatically locked due to age.

twister5800 · Answer

Thanks to you both for replying!  Do you also have the interface to the DHCP server listed in the "Interfaces" box?   Exactly THIS fixed my problems, now it works out of the box and it's stable!! [;)]  Should have read the manual more thoroughly [8-)]:  Add the interfaces involved.  Add the interface to the DHCP server as well as all interfaces to the clients' network(s) between which DHCP requests and responses should be forwarded.   Again THANKS [:)]