Digi IX40 User Manual page 459

Virtual Private Networks (VPN)
7. (Optional) Set a key that will be inserted in GRE packets created by this tunnel.
The key must match the key set by the remote endpoint.
(config vpn iptunnel gre_example)> key value
(config vpn iptunnel gre_example)>
where value is an interger between 0 and 4294967295, or an IP address.
8. (Optional) Enable the device to reply to Cisco GRE keepalive packets:
(config vpn iptunnel gre_example)> keepalive true
(config vpn iptunnel gre_example)>
9. (Optional) Enable the device to allow packets destined for an address which is not explicitly in
the routing table to exit the IP tunnel:
(config vpn iptunnel gre_example)> open_routing true
(config vpn iptunnel gre_example)>
10. Save the configuration and apply the change
(config vpn iptunnel gre_example)> save
Configuration saved.
>
11. Type exit to exit the Admin CLI.
Depending on your device configuration, you may be presented with an Access selection
menu. Type quit to disconnect from the device.
IX40 User Guide
Generic Routing Encapsulation (GRE)
459