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MinasTtirittis
MinasTtirittis
New Member
July 9, 2025
Question

Issue Summary: FortiGate 200F & FortiSwitch Connectivity Problems

  • July 9, 2025
  • 3 replies
  • 1380 views

I'm currently facing network issues involving a FortiGate 200F (firmware version 7.4.8) and two FortiSwitches (models S548 and S458), both running version 7.6.2.

Over the past three weeks, since upgrading the switches to 7.6.2, the network has become slow, intermittently unresponsive, and frequently disconnects devices.

Additionally, when accessing the topology view, not all switch-to-switch connections are visible or properly displayed.

3 replies

Richie_C
Staff
Richie_C
Staff
July 9, 2025

Hi @MinasTtirittis 

 

Its difficult to know what is happening here. Maybe some of the following information would help to diagnose the problem:

 

  • Are there any switch events in the logs?
  • Are the switches in FortiLink mode or standalone?
  • Features being used, such as MCLAG, L3 routing, NAC.....

Regards

    MinasTtirittis
    MinasTtirittisAuthor
    New Member
    July 9, 2025

    Hi @Richie_C 

    Yes, the switches are configured in FortiLink mode, and the first two are running in an MCLAG setup.

    Please let me know if you need any specific logs or details regarding features like NAC or L3 routing.

    Regards,

    Richie_C
    Staff
    Richie_C
    Staff
    July 9, 2025

    Ok, I would start by checking the config and status of the MCLAG. The following commands should give you an idea of the status:

     

    diagnose switch-controller switch-info mclag list  diagnose switch-controller switch-info mclag icl

     

    You should make sure that the correct interfaces are recognised as either MCLAG or ICL interfaces. 

     

    You can also check the status of the link aggregation interfaces. The following guide is a good reference:

     

    https://community.fortinet.com/t5/FortiGate/Technical-Tip-Initial-troubleshooting-steps-for-LACP-Link/ta-p/198339

     

    Regards

    Richard  

    Richie_C
    Staff
    Richie_C
    Staff
    July 9, 2025

    For the logs. It would be interesting to know if there are any interfaces flapping or spanning tree events to start with.

    HarryTran
    Staff
    HarryTran
    Staff
    July 31, 2025

    For "not all switch-to-switch connections are visible or properly displayed.", it runs in to a known bug 1174647

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