Perfect Forward Secrecy:
option to enable the Perfect Forward Secrecy
(PFS) in the IPSec VPN. A PFS DH group will be needed if PFS is enabled.
A Site to Site Client set up is very similar to that of a Gateway, with additional
setting of a Remote Server IP address.
All the client settings must match those used in the gateway (server), such
as FQDN, Security Types, Keys, and Encryption Functions.