Using EMS SN verification to enhance VPN security
The EMS serial number (SN) verification feature restricts establishing a VPN connection to the FortiGate to only licensed FortiClient endpoints. The EMS SN verification is performed by the FortiGate and the feature requires that the FortiGate and FortiClient endpoints both must be connected to the same FortiClient EMS. See Enhancing VPN security using EMS SN verification for more information.