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SFP+ Module compatibility

I had a few spare SFP+ modules that I want to implement in the fortilink ports as we are replacing our switch stacks. These modules are third party.

I tried connecting them and I was able to get a link light on the X2 port on the firewall but no link lights on the switch. The fibre connections are crossed correctly but I don’t get an uplink on the fortiswitch.

Any ideas?
Valued Contributor II

Hello @andej ,


If you are sure that SFP is compatible with Fortigate and Switch, you can try to change the interface speed. Generally, problems are solved this way.



config system interface
edit <interface-name>
set speed <1000full/10000half/100full/100half/10full/10half/auto>

If you have found a solution, please like and accept it to make it easily accessible to others.
NSE 4-5-6-7 OT Sec - ENT FW
If you have found a solution, please like and accept it to make it easily accessible to others.NSE 4-5-6-7 OT Sec - ENT FW

Hello  @andej ,


Thank you for contacting the Fortinet Forum portal.

As @ozkanaltas  mentioned, most problems would be compatibility of the SPF or speed.

please refer below links to verify the transceiver on fortiswitch and fortigate and to adjust the speed.


Best regards,



If you feel the above steps helped resolve the issue, mark the reply as solved so that other customers can get it easily while searching for similar scenarios.


In my experience I got over 90% of third party SFP(+) working on Fortinet devices, so you shouldn't have an issue with compatibility, just make sure both ends are of the same type (i.e: both short wave, or both long wave) and use the right cable.

On the other hand I think Fortinet may not support you in case you have any related issue.


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