Draytek Vigor2912 Series User Manual page 275

Confirm Pre-Shared Key- Retype the characters to
confirm the pre-shared key.
Note: Any packets from the remote dial-in user which does
not match the rule defined in VPN and Remote
Access>>Remote Dial-In User will be applied with the
method specified here.
Medium - Authentication Header (AH) means data will be
IPsec Security Method
authenticated, but not be encrypted. By default, this option
is active.
High (ESP) - Encapsulating Security Payload (ESP) means
payload (data) will be encrypted and authenticated. You
may select encryption algorithm from Data Encryption
Standard (DES), Triple DES (3DES), and AES.
After finishing all the settings here, please click OK to save the configuration.
265 Vigor2912 Series User's Guide