| GRE | Enables the whole GRE subsystem, the default value is “Off”. |
| GRE tunnels | Each row/record corresponds to one GRE tunnel. There should not be more than 20 simultaneous GRE tunnels (recommendation). The Key/Primary Field of the table is “Peer address”, which uniquely identifies each tunnel. |
| Peer address | The IP address of a remote GRE tunnel end-point. This end-point IP address must be unique and cannot be used for more than one tunnel. The local address (interface) is automatically selected based on the destination address type. Addresses on both ends must correspond to each other. |
| Tunnel IP/MASK | The tunnel IP address and mask. The network defined by this item must cover only the local tunnel address and remote end-point address. Both tunnel end-points must be within the same subnet, but IP addresses must be different. The remote end-point IP address is used as a “Gateway” for tunnel configuration. The network mask can even be /31 (255.255.255.254), because it is a p2p (no need for a network address and a broadcast address). |
| Note | The tunnel description. |
| Active | Enables or disables the particular tunnel. |
Routing into the GRE tunnels can be configured in the Routing menu. The Gateway must be set as a remote end-point GRE tunnel IP address.