Technical Note : SSLVPN client in tunnel mode may fail to connect via SSL VPN tunnel mode

In the SSLVPN tunnel mode settings on the FortiGate, certain users may not be able to connect via SSL VPN tunnel mode or FortiClient. This could be due to an older driver .inf file for the SSL VPN client remaining in the system and causing the connection to fail.

Two possible solutions to correct this issue are given below:

1. Search the oem*.inf file for "pppop" in Windows. If there is more than one .inf file having "pppop", leave the latest one, remove all the older files, together with the matching .pnf file. Also remove the INFCACHE.* file.

Reboot the PC and  following the reboot the SSL VPN Client will be able to connect to the SSLVPN tunnel successfully.

2. Install FortiClientsslvpnsetup build2148 or above and then uninstall it. During the uninstall process, there will be an extra action performed which will delete all the older drivers from the system.

Finally, reinstall Forticlientsslvpnsetup and the SSL VPN Client will be able to connect to the SSLVPN tunnel successfully.