This option lets you define which method of authentication may take place.
Currently there are two options:
- Shared Key: Both parties agree on a "secret", much like a password.
- X.509 Certificate: The client is required to present a certificate, signed by the VPN server. If this signature if validated then access is granted.
Both schemes require a key/certificate to be made in the Keys and
Certificates section. Please refer to your EnGarde documentation for a
more detailed discussion.