In the window Manual Keying you have to enter the encryption and
authentication keys the partner VPN gateway requires. Depending on the selected
encryption and authentication services in the previous page (IPSec Connection
Properties) you will get some of the following text fields.
DES Encryption Key
3DES Encryption Key
SHA1 Authentication Key
MD5 Authentication Key
Manual keys must be entered in the hexadecimal format, otherwise the error message "Incorrect Encryption Key" will appear.
SPI (Security Parameter Index) are indices to keep the IPSec Connection tunnels distinct. A security association (SA) is defined by destination, protocol and SPI. Without the SPI, connections to the same gateway using the same protocol cannot be distinguished.