SonicWALL TZ 190 Manuale Utente

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Network > WAN Failover & Load Balancing
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SonicOS Enhanced 4.0 Administrator Guide
About Source and Destination IP Address Binding
When you establish a connection with a WAN, you can create multiple interfaces, dividing up 
the task load over these interfaces. There are both Primary and Secondary WAN interfaces. 
This task distribution model maintains high performance, ensuring that one interface does not 
become an impasse to the point where it blocks traffic from passing. This process is WAN Load 
Balancing. 
While WAN Load Balancing addresses performance challenges, it can create other problems, 
including losing track of sessions. Session confusion can occur because some applications fail 
to adequately track multiple user sessions Load Balanced on multiple interfaces. These 
applications treat incoming packets as originating from different users because they use IP 
addresses to differentiate user sessions instead of application-layer user identification tags.
To ensure that you have proper connectivity in all applications, SonicWALL provides a feature 
called Source and Destination IP Addresses Binding, a solution that maintains a consistent 
mapping of traffic flows with a single outbound WAN interface.
Setting Up WAN Failover and Load Balancing
Perform the following steps to configure WAN Failover and Load Balancing on the SonicWALL 
security appliance:
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Configuring an Interface as a Secondary WAN Port
On Network > Interfaces page, configure the chosen port to be in WAN zone, and enter in the 
correct address settings provided by the Secondary ISP. In the example, the SonicWALL 
security appliance is acquiring its secondary WAN address dynamically from ISP #2, using 
DHCP. Any interface added to the WAN zone by default creates a NAT Policy allowing internal 
LAN subnets to NAT out this Secondary WAN interface.