This chapter contains the following sections:
For Failover & Load Balancing (LB),
multiple interfaces on the SonicWALL security appliance can be configured as part of a load balancing group. Up to “N-1” interfaces on the SonicWALL security appliance can be configured as part of a load balancing group, where N is the total number of physical interfaces on the appliance. (At least one interface must always be configured for the LAN zone.)
One of the interfaces can be specified as the Final Backup interface. On most SonicWALL
security appliances, the U0 interface (for an external analog modem or 3G device) is configured as the Final Backup interface by default. This can be modified to specify any member of the LB group as the Final Backup.
Depending on your appliance, when an analog modem or 3G device is installed prior to starting
the appliance, it will be listed as the U0, U1, or M0 (NSA 240 only) interface. These interfaces can be configured for the following functions:
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Failover connection
– To use the analog/3G interface as a failover connection, configure it in the Final Backup position in the Default LB Group.
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Primary Internet connection
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To use the analog/3G interface as the primary Internet connection, configure it in the Final Backup position of the LB Group.
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Member of a load balancing group
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To use the analog/3G interface as an always connected member of a load balancing group, configure it as a member of the Interface Ordering section of the LB Group.
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T
he Failover and Load Balancing settings are described below:
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Enable Load Balancing
– This option must be enabled for the user to access the LB Groups and LB Statistics section of the Failover & Load Balancing configuration. If disabled, no options for Failover & Load Balancing are available to be configured.
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Respond to Probes
– When enabled, the appliance can reply to probe request packets that arrive on any of the appliance’s interfaces.
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Any TCP-SYN to Port
– This option is available when the Respond to Probes
option is enabled. When selected, the appliance will only respond to TCP probe request packets having the same packet destination address TCP port number as the configured value.
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