Fortinet fortigate-200a Betriebsanweisung

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VPN 
Redundant IPSec VPNs
FortiGate-200A Administration Guide
01-28006-0072-20041105
 289
See 
6
Arrange the policies in the following order:
• outbound encrypt policies
• inbound encrypt policy
• default non-encrypt policy (Internal_All -> External_All)
Redundant IPSec VPNs
To ensure the continuous availability of an IPSec VPN tunnel, you can configure 
multiple connections between the local FortiGate unit and the remote VPN peer 
(remote gateway). With a redundant configuration, if one connection fails, the 
FortiGate unit establishes a tunnel using the other connection. 
The configuration depends on the number of connections that each VPN peer has to 
the Internet. For example, if the local VPN peer has two connections to the Internet, 
then it can provide one redundant connection to the remote VPN peer. 
A single VPN peer can be configured with up to three redundant connections.
The VPN peers are not required to have a matching number of Internet connections. 
For example, between two VPN peers, one peer can have multiple Internet 
connections while the other has only one Internet connection. In the case of an 
asymmetrical configuration, the level of redundancy varies from one end of the VPN to 
the other. 
Configuring redundant IPSec VPNs
For each FortiGate unit, first add multiple (two or more) external interfaces. Then 
assign each interface to an external zone. Finally, add a route to the Internet through 
each interface. 
Source
The local VPN spoke address.
Destination
External_All
Action
ENCRYPT
VPN Tunnel
The VPN tunnel name added in step 
. (Use the same tunnel for all encrypt 
policies.)
Allow inbound Select allow inbound.
Allow outbound Do not enable.
Inbound NAT
Select inbound NAT if required.
Outbound NAT Select outbound NAT if required.
Note: The default non-encrypt policy is required to allow the VPN spoke to access other 
networks, such as the Internet.
Note: IPSec Redundancy is only available to VPN peers that have static IP addresses and that 
authenticate themselves to each other with preshared keys or digital certificates. It is not 
available to VPN peers that have dynamically assigned IP addresses (dialup users). Nor is it 
available to VPN peers that use manual keys.