User`s guide

Connection Timeout
The time in seconds to allow before a failing connection skips to the
next fallback level. For a faster failover, enter lower values. For
congested connections, enter longer values. Default: .30
NAT Type
The type of NAT to use. The availability of the following settings
depends on the NAT type that you select. This setting lets you specify
which source IP address and interface are to be used in case of
fallback. This is especially important if you are using multiple ISPs.
Connecting via the backup provider using the wrong source IP
address causes the return traffic routing to fail.
Select one of these options:
Dynamic Source NAT – The firewall uses the routing table to
find a suitable interface for routing the packet and uses the IP
address of the relevant interface as the new source IP address.
No Source NAT – The original source IP address of the packet
is not changed.
From Interface – Source NAT using the first IP address on the
interface that is selected from the list.Interface
Explicit – Uses the IP address that is entered in the Explicit IP
field.Address
Proxy ARP
If the explicitly defined IP address does not exist locally, select this
check box to create an appropriate Proxy ARP entry. This option is
only available if has been chosen as . Explicit NAT Type
Proxy ARP makes it possible for ARP requests to be answered for IP
addresses that are not implemented in the Barracuda Firewall.
PAT
Uses Port Address Translation (PAT). PAT is also known as NAT
overloading. PAT extends NAT so that port numbers are also
translated. Use it to pool several private IP addresses to one public IP
address. PAT can be enabled or disabled if you select either From
or from the list. It is always enabled for Interface Explicit NAT Type
and it is always disabled for .Dynamic Source NAT No Source NAT
Weight Assigns a weight number to this interface. This is only used if the Mul
selected in the section istilink Policy Failover and Load Balancing
. Specify the value relative to the weightsWeighted Round Robin
assigned to the other interfaces. A higher value means that this
interface is used proportionally more.
Predefined Connection Objects
Name Description
Default (SNAT)
Source NAT using the local IP address obtained from a routing
lookup to the destination.
No SNAT
Connection is established using the original source IP address.
SNAT with DSL IP
Source NAT using the first IP found on DSL interface ppp1.address
SNAT with 3G IP
Source NAT using the first IP found on 3G interface ppp5.address
SNAT with DHCP IP
Source NAT using the first IP found on interface dhcp.address
Failover and Link Load Balancing
Multiple source IP addresses and interfaces can be specified in the same connection object. This allows failover or session-based balancing
between up to four links. Balancing can be achieved using either a round robin or weighted random algorithm. For more information, see Exampl
e - Creating Connection Objects for Failover and Link Balancing.