Problem two FG-TRAN-GC FGT300D

[MedWell]

I have FGT300D, her power is off, I installed two transceivers  FG-TRAN-GC (her out-put is RJ45) in the port SFP (port 5 and port 6), then, I start the power on.

I configured port5 (192.168.1.254/24) and port6 (192.168.5.0/24), each port is in her LAN, I put PC1 or switch2 in port5, it’s connected,  if I put PC2 or switch2 in port6 will be connect and will be down after 4 seconds

If I reverse interconnection PC/switch, I connect  PC1 in port6 then PC2 in port5, the PC1 is connected and the PC2 not connected (same problem).

I conclude, if I install two transceivers  FG-TRAN-GC in Port SFP, one port  will be connect and the other port will be not connect.

[MedWell]

After, putting a transceivers in my FortiGate, It's necessery to change any parameter?

[MrSinners · Accepted solution]

No paramters are needed, they work right away. You might want to try to set speed to a fixed amount at the interface configuration with "speed 1000" and see if that improves the situation. Both transceivers should work independently from each other, so it seems to be a misconfiguration.

You configured port5 and port6 each with a different subnet, but both are in the same LAN? What do you mean? Are you using a virtual switch called "lan"?