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Tunnels
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The basic parameters for a tunnel are :-
•
name
: name of the tunnel (OPTIONAL)
•
local-id
: the Local ID to use for the tunnel (REQUIRED)
•
remote-id
: the ID used at the far-end for this tunnel (this will be the Local ID used on the far-end for
this tunnel) (REQUIRED)
•
secret
: this is a pre-shared secret string that must be set to the same value in the tunnel definitions on
both end-point devices
•
ip
: the IP address of the far-end end-point device (OPTIONAL)
The far-end IP address is optional, and if omitted, tunnel wrapper packets will be sent to the IP address from
which wrapper packets are being received (if any). As such, at least one of the two end-points involved must
have a far-end IP address specified, but it is not necessary for both ends to specify the other. This allows you
to setup a tunnel on an end-point without knowing (or caring) what the far-end IP address is ; this means you
can handle cases such as one of end-points being behind a NAT router that has a dynamic WAN IP address,
or can be used to simplify administration of end-points that are used to terminate a large number of tunnels,
by omitting the far-end IP address in tunnel definitions on such 'shared' end-points. The latter case is typical
where an ISP deploys a FireBrick device to provide a 'head-end' device for tunnel bonding.
If you wish to use a different UDP port number than the default of 1, specify the port number using the
port
attribute.
11.1.3. Viewing tunnel status
The status of all configured FB105 tunnels can be seen in the web User Interface by selecting "FB105" from
the "Status" menu. The tunnels are listed in ascending Local ID order, showing the far-end IP in use, the tunnel
name, and the state. The table row background colour is also used to indicate tunnel state, with green for Up
and red for Down.
Note that there is a third state that a tunnel can be in, that is "Up/Down" **TBC confirm** - this indicates
that tunnel wrapper packets are being received, but that they are informing this end-point that the far-end is
not receiving tunnel wrapper packets. This means the tunnel is essentially only established unidirectionally,
typically because of a firewalling, routing, NAT or similar issue that is prevent the correct bidirectional flow
of tunnels wrapper packets between the tunnel end-points.
Tunnel status can also be seen using the
show fb105
CLI command - see Appendix G.
11.1.4. Dynamic routes
Since a tunnel can only carry traffic properly when in the Up state, any traffic routed down a tunnel that is
not Up will be discarded. The ability to dynamically create a route when the tunnel enters the Up state (and
automatically delete the route when the tunnel leaves the Up state) allows the route to be present only when
traffic can actually be routed down the tunnel. In combination with the use of route preference values, you can
use this to implement fall-back to a less-preferred route if the tunnel goes down. Alternatively, you may want
to intentionally use a different tunnel to carry traffic, and use profiles to enable/disable tunnel(s) - the dynamic
route creation means that you do not need to manually change routing information to suit.
A dynamic route is defined by setting the
routes
attribute on the tunnel definition, specifying one or more
routing destinations in CIDR format, as discussed in Section 7.1.
11.1.5. Tunnel bonding
Multiple FB105 tunnels can be bonded together to form a set, such that traffic routed down the bonded tunnel
set is distributed across all the tunnels in the set. This distribution is done on a round-robin per-packet basis
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