Issue with DNS after disconnecting from VPN session

Forum|Forum|1 year ago
July 7, 2025
3 replies
2215 views

For security resons, we do not allow our users to modify network interface settings on their computers. When they connect to a VPN session using the FortiClient application, the DNS settings get temporarily changed to a static entry.
Under some unknow circumstances, sometimes a client will loose or close iis connection and the DNS remains overiden. When this happends, the user is unable to access any network ressources until someone with sufficient security privileges resets

This situation occurs a few times every week and our users are getting acreasingly irritated.Could anyone please help us resolve this issue?

FortiClient EMS

adhawan

Staff

Hi
I suggest ensuring that the network drivers on the affected PCs are up to date. Outdated drivers can cause network connection issues.
Verify if any recent Windows updates have been installed, as they might cause network connection issues.
Ensure that the FortiClient version is the latest one available. Upgrading to the latest version can fix known issues and improve compatibility. By following these steps, you should be able to mitigate the issue of DNS settings remaining overridden after VPN disconnection.

VinayHM

Please check the ssl vpn settings regarding DNS

dns server sam as client system dns

And from portal assigned to the user

GJStefou

Explorer

Hi,

First thing you have to check is the version of FC VPN you're using and the known issues this version have.

I have seen that heppening with IPSec VPN connections on some FC VPN versions.

When closing the VPN tunnel from FC VPN the tunnel wouldn't drop completely, we have to shutdown the FC VPN application from the Tray Notification area on windows.

At some cases, it helped when we uninstalled and re-installed the application using RevoUnistaller so everything cleaned up properly.

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