I have a Fortigate 60C connected to two ISPs, one via LTE USB dongle (LTE , let's call in "Internet A"), and another one connected via fixed broadband (let's call this one "Internet B"). Out of 4 LAN ports, 2 are routed ONLY to Internet A, and the other 2 ONLY routed to Internet B. SSLVPN client is established so that Forticlient can establish SSLVPN tunnels to this Fortigate via Internet B, and get access to Internet A.
THe problem is , it works on some PC but not the others for some strange reasons I suspect that it's due to the IP address of DNS servers.
PC can connected to LAN via VPN (IPsec, or PPTP or ….etc) over the Internet and are assigned to a separate subnet
Please refer to the diagram for details.
Host Name: FGT60C3G13022553 [Change]
Serial Number: FGT60C3G13022553
Operation Mode NAT [Change]
HA Status Standalone [Configure]
System Time Tue Aug 8 04:32:25 2017 (FortiGuard) [Change]
Firmware Version v5.0,build0292 (GA Patch 9) [Update] [Details]
Specifications of the USB dongle and the configuration done on it: