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Curtava
New Member
October 19, 2025
Question

Vpn kicking users out

  • October 19, 2025
  • 2 replies
  • 375 views

Anyone else seeing fortigate vpn users randomly getting disconnected even though the tunnel looks active? Seems to happen more when network traffic is high.Could it be bandwidth limits ?

    2 replies

    esalija
    Staff
    Staff
    October 21, 2025

    Dear @Curtava 

     

     

    Yes, random disconnections for FortiGate VPN users, especially during high network traffic, can be related to bandwidth limits or other network path issues. Here are some steps to troubleshoot and address the issue:

    Check Bandwidth Limits: Ensure that there are no bandwidth limits set on the VPN tunnel that could be causing disconnections during high traffic periods.
    Network Path Issues: Verify if any network path issues such as ISP traffic shaping, rate-limiting, or packet loss could be affecting the VPN connection.
    NAT Device Timeouts: Check if NAT device timeouts are closing translation entries for idle connections, which can cause disconnections.
    Keepalive Configuration: Ensure that keepalive messages are configured to maintain the tunnel's active state and prevent it from going idle.
    Debugging: Use diagnostic commands to capture and analyze traffic, such as diagnose sniffer packet and diagnose debug application ike -1, to identify any specific issues causing the disconnections.

    https://community.fortinet.com/t5/FortiGate/Technical-Tip-Understanding-and-Troubleshooting-IPSec-VPN/ta-p/397214

    Best regards,

    Erlin

     

     

    Curtava
    CurtavaAuthor
    New Member
    October 22, 2025

    How do you tell if it’s bandwidth or NAT timeout causing it??

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