Netopia 3346N-ENT User Guide (en)

Virtual Private Networks (VPNs)   5-11
About GRE Tunnels
Generic Routing Encapsulation (GRE) protocol is another form of tunneling that Netopia routers suppor t. A GRE 
tunnel is brought up when a valid GRE profile is installed, and brought down when the profile is disabled, or 
GRE tunnels are not connection-based, but rather are installed and simply wait for GRE packets. There is no 
special star tup initiation as with PPPoE or PPTP. GRE is best adapted to simple routing and/or tunneling, and is 
not for use with any sensitive data. GRE offers no encr yption; and authentication of data integrity is limited to 
checksum verification, if enabled.
To set up a GRE tunnel, you create a Connection Profile including the IP address and other relevant information 
for the remote par tner.
When you define a Connection Profile as using GRE by selecting GRE as the Encapsulation Type, and then 
select Encapsulation Options, the GRE Tunnel Options screen appears.
Add Connection
                             Add Connection Profile
         Profile Name:                      Profile 2
         Profile Enabled:                 +-------------+
         Encapsulation Type...            | PPP         |
         Underlying Encapsulation...      | ATMP        |
                                          | PPTP        |
         Encapsulation Options...         | IPsec       |
                                          | L2TP        |
                                          | GRE         |
         IP Profile Parameters...         +-------------+
         Interface Group...                 Primary
         COMMIT                             CANCEL