Troubleshooting Tip: WAN1 and WAN2 fiber interfaces showing as down after upgrading FortiGate-80F from v7.4.7 to v7.4.8

After upgrading FortiGate-80F to v7.4.8, the interfaces of wan1 and wan2 are showing as down if a fiber connection was used before the upgrade. To confirm the status, the following should be checked:

1. Both wan1 and wan2 interface ports are connected with fiber cables.
2. Issue the following command to confirm that SFP readings are healthy:

get system interface  transceiver

3. Run the following commands to verify if the interface Admin status is up:

diagnose hardware deviceinfo nic wan1

diagnose hardware deviceinfo nic wan2

Sample output:

========== Link Status ==========
Admin :up
netdev status :down
autonego_setting :1
link_setting :1
speed_setting :1000
duplex_setting :0
Speed :10
Duplex :N/A
link_status :Down

4. Run the following command to check the physical interface settings:

get system interface physical wan1

get system interface physical wan2

The medium is showing as copper; the issue faced matches a known issue reported for FortiGate-80F v7.4.8:

FGT # get system interface physical wan2
== [onboard]
        ==[wan2]
                mode: static
                ip: 1.1.1.1 255.255.255.255
                ipv6: ::/0
                status: down
                speed: n/a
                medium: copper
                FEC: none
                FEC_cap: none

This issue has been resolved in:
v7.4.9 (available to download from the Fortinet support portal).
v7.6.4 (available to download from the Fortinet support portal).
v8.0.0 (scheduled to be released in March 2026).
These timelines for firmware release are estimated and may be subject to change.

The workaround is to set the medium type to fiber manually using the following CLI commands:

diagnose hardware shared-port wan1 fiber

diagnose hardware shared-port wan2 fiber

The commands need to be issued on Primary and Secondary devices separately if HA is configured.