Fortiswitch FS-108F DHCP IP Problem over Fiber

[michaelchristianlbt]

We connect a Lancom Router via Fiber to the SFP Port in the FortiSwitch.
We recieve a IP Adress from the LancomRouter on the SFP (tested with TestDevice)

But there is no forwarding of the IP adress to the LAN Ports. So when we connect a device to these Ports they do not get an DCHP IP adress from the Lancom Router.

But when wie try it with a connection via RJ45 from the Lancom Router to a LanPort RJ45 in the Fortiswitch it is all fine and we get a IP on the other Lan Ports of the Switch.

But again we also recive a IP direct on the SFP from the Lancom ROuter if we do this SFP in another Testdevice.

The SFP is FN-TRAN-SX from Forti

[AEK]

If I understand well your issue, check if DHCP snooping is enabled on the affected port.

[michaelchristianlbt]

Thank you AEK.  but there is no change if it is on or off :(

[AEK]

You may have missed to put the SFP port on the same VLAN as the client ports, I mean maybe it is currently a trunk. Can you check?

[ebilcari]

As a start you can check if the switch learns any MAC address on the SFP port, from CLI:

diagnose switch mac-address list | grep port9

If there is no MAC address learned on that port, than something is wrong with L2 link and you have to troubleshoot SFP port.

[michaelchristianlbt]

still no solution, we used another Switch from netgear ;)

[michaelchristianlbt]

thanks to all :)