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Tunnels
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specified as a permissible range. Note that in this case the identity the peer provides when it attempts to set
up the connection will be used to select the matching configuration connection details. The local-ip is optional
- if omitted the IP used by the peer to reach the FireBrick is used for a connection initiated remotely, and
the FireBrick chooses a suitable source IP when it initiates a connection. You can also optionally specify an
internal-ipv4 and/or an internal-ipv6 address. When specified, these addresses are used for the source address
of the tunnelled packet when the FireBrick sends traffic it originates itself down the tunnel (unless the source
address has already been specified by some other means). If these are not specified the FireBrick will use the
tunnel's local-ip setting when appropriate.
Note that although obviously the tunnel endpoint addresses must be the same type of address (both IPv4 or
both IPv6) the traffic sent through the tunnel may be IPv4, IPv6 or a mixture of the two.
11.1.2.4.5. Road Warrior connections
A Road Warrior connection provides a VPN service to which multiple clients can connect. A Road Warrior
connection must have its roaming-pool item set to the name of an IKE roaming IP pool entry defined in the top
IPsec configuration section (see above). The connection mode must be set to Wait and no routing information is
required as the FireBrick automatically routes traffic for the allocated IP(s) to the VPN client. A Road Warrior
connection will typically use certificate authentication for the local FireBrick server and EAP for the connecting
client as this is what most clients expect, but other authentication methods can be used if supported by the client.
11.1.2.4.6. Routing
Apart for Road Warrior connections you must configure routing to specify which traffic the FireBrick should
send out through the tunnel. The routing configuration uses the same style as used elsewhere in FireBrick
configuration. A simple set of IPs and/or IP ranges can be specified in the routes attribute, or for more complex
routing a number of separate route elements can be added to the tunnel config. Metrics and the routing tables
to be used may also be specified. The blackhole option can be set to ensure that traffic to be routed down the
tunnel is discarded if the tunnel is not up. If not set, the normal FireBrick routing rules could select an alternate
inappropriate transmission path, thus compromising security.
11.1.2.4.7. Other parameters
A graph may be specified to monitor data through the tunnel. A speed may be set to rate-limit the traffic.
mtu can be used to specify a maximum MTU value for tunnelled packets. Packets longer than this size will
be fragmented or rejected using the normal IP fragmentation mechanism before being encapsulated. Note that
after encapsulation of a packet the resulting packet may become too large to transmit using the MTU of the
path used to transmit the tunnel traffic, in which case the encapsulated packet will be fragmented as usual. In
some situations (for example where there are poorly implemented intervening NAT devices) such fragments
may be dropped. In this case, the mtu setting can be useful to reduce the maximum size of the inner packets,
so the encapsulated packets do not themselves need to be fragmented.
tcp-mss-fixcan be set to attempt to avoid fragmentation in TCP sessions, by adjusting the TCP SYN header so
that the negotiated TCP MSS will fit in the tunnelled MTU.
log, log-error and log-debug can be used to steer IKE logging information which is specific to this connection
to a selected logging target.
dead-peer-detectcan be set to the period (in seconds) used between checks that the connection is still live (ie
the peer is responding). It defaults to 30 for normal connections, and 0 (off) for Road-Warrior connections.
lifetime can be set to the period required between rekeying. The default is 1:00:00 (1 hour). The FireBrick will
renegotiate the connection shortly before it reaches this period since the last renegotiation. Note that if dead-
peer-detection is set to 0 (off) a dead peer will not be noticed until renegotiation is attempted.
11.1.2.5. Setting up Manual Keying
To set up a new manually-keyed IPsec tunnel select "Add: New IPsec manually-keyed connections" on the
top-level IPsec setup page.
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