Gre Tunnel - Teltonika RUT104 User Manual

4.7.2

GRE Tunnel

GRE (Generic Routing Encapsulation RFC2784) is a solution for tunneling RFC1812 private
address-space traffic over an intermediate TCP/IP network such as the Internet. GRE tunneling does
not use encryption it simply encapsulates data and sends it over the WAN.
WAN IP:
A.A.A.A
LAN1 192.168.0.0/24
192.168.0.2
Figure 20. Typical GRE tunnel application connecting two remote networks
In the example network diagram (Fig. 20) two distant networks LAN1 and LAN2 are connected.
To create GRE tunnel the user must know the following parameters:
1. Source and destination IP addresses (From Fig. 22 A.A.A.A and B.B.B.B).
2. Tunnel local IP address
3. Distant network IP address and Subnet mask
Enable GRE Tunnel. Check the box to enable the GRE Tunnel function.
TTL. Specify the fixed time-to-live (TTL) value on tunneled packets [0-255]. The 0 is a special
value meaning that packets inherit the TTL value.
Enable PMTUD. Check the box to enable the Path Maximum Transmission Unit Discovery
(PMTUD) status on this tunnel.
Remote tunnel endpoint IP address. Set remote tunnel Endpoint IP address.
Remote network IP address. Specify remote LAN IP address.
Remote CIDR. Specify remote LAN Subnet CIDR value.
MTU. Specify the maximum transmission unit (MTU) of a communications protocol of a layer
in bytes.
Internet
Tunnel 10.0.0.1/24
GRE tunnel
Figure 21. GRE tunnel settings
WAN IP:
B.B.B.B
Tunnel 10.0.0.2/24
LAN1 192.168.1.0/24
LAN2 192.168.1.2
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