Cradlepoint COR IBR350 Manual page 100

GRE Tunnels
Generic Routing Encapsulation (GRE) tunnels can be used to create a connection between two private networks. Most Cradlepoint routers are
enabled for both GRE and VPN tunnels. GRE tunnels are simpler to configure and more flexible for different kinds of packet exchanges, but VPN
tunnels are much more secure.
In order to set up a tunnel you must configure the following:
• Local Network and Remote Network addresses for the "Glue Network," the network that is created by the administrator that serves as
the "glue" between the networks of the tunnel. Each address must be a different IP address from the same private network, and these
addresses together form the endpoints of the tunnel.
• Remote Gateway, the public facing WAN IP address that the local gateway is going to connect to.
• Routes that allow you to configure what network traffic from local host(s) will be allowed through the tunnel.
• Optionally, you might also want to enable the tunnel Keep Alive feature to monitor the status of a tunnel and more accurately determine if
the tunnel is alive or not.
Optionally, you might also want to enable the tunnel Keep Alive feature to monitor the status of a tunnel and more accurately determine if the
tunnel is alive or not.
Click Add to configure a new GRE tunnel; click Edit to make changes to an existing tunnel.
Add/Edit Tunnel – General Tunnel Name: Give the tunnel a name that uniquely identifies it.
Tunnel Key: Enables an ID key for a GRE tunnel, which can be used as an identifier for mGRE (Multipoint GRE).
Local Network: This is the local side of the "Glue Network," a network created by the administrator to form the tunnel. The user creates the IP
address inputted here. It must be different from the IP addresses of the networks it is gluing together. Choose any private IP address from the
following three ranges that doesn't match either network:
• 10.0.0.0 - 10.255.255.255
• 172.16.0.0 - 172.31.255.255
• 192.168.0.0 - 192.168.255.255
Remote Network: This is the remote side of the "Glue Network." Again, the user must create an IP address that is distinct from the IP addresses
of the networks that are being glued together. The Remote Network and Local Network values will be flipped when inputted for the other side of
the tunnel configuration.
Subnet Mask: This is the subnet mask for the Glue Network. The Local and Remote Network addresses must fit with this mask. 255.255.255.0 is
a logical choice for most users.
Remote Gateway: This is the public facing, WAN-side IP address of the network that the local gateway is going to connect to.
Figure 129: GRE Tunnels
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