As GRE does not have its own mechanism to encrypt traffic it depends on IPsec for getting the encryption job done. The Main point of GRE over IPsec is to encrypt what is encapsulated by GRE. The following Instruction will guide you through the WEB GUI configuration.

Two NB1600 connected together through LAN1 GRE tunnel was established through this network and IPSec tunnel create through this GRE tunnel.

The configurations of two NB1600 are as below:

Configure of Box1:

Configure of Box2: