SonicWALL 3 Benutzerhandbuch

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The Failover page in the Modem Setting window includes the same settings on the Modem > 
Failover page. If you configured the failover settings on the Modem > Failover page, they are 
displayed in the Failover page. If you have not configured Failover settings, use the following 
instructions to configure the Failover Settings:

1 Select Enable WAN Failover.

2 Select Enable Preempt Mode if you want the primary WAN Ethernet interface to take over from 

the secondary modem WAN interface when it becomes active after a failure. If you do not enable 
Pre-empt Mode, the secondary WAN modem interface remains active as the WAN interface until 
you click Disconnect. 

3 Select Enable Probing. Probing for WAN connectivity occurs over the Ethernet connection, the 

dial-up connection, or both. When probing is disabled on the Ethernet link, the SonicWALL 
security appliance only performs link detection. If the Ethernet connection is lost for a duration of 
5-9 seconds, the SonicWALL security appliance considers the Ethernet connection to be 
unavailable. If the Ethernet link is lost for 0-4 seconds, the SonicWALL security appliance does not 
consider the connection to be lost. If you are swapping cables quickly, unnecessary WAN failover 
does not occur on the SonicWALL security appliance. If probing is enabled and the cable is 
unplugged, the 5-9 seconds link detection does not occur. Instead, the probing rules apply to the 
connection using the parameters configured for Probe Interval (seconds) and Failover Trigger 
Level (missed probes) settings. If probing is enabled on dialup, the dialup connection is 
terminated and re-established when probing fails over the modem. 

4 Select an option from the Probe through menu. Select Ethernet Only to probe the Ethernet WAN 

connection and failover to the modem when the connection is lost. Select Modem Only to probe a 
dial-up connection and have the modem redial when the dial-up connection is lost. Select Modem 
and Ethernet to enable both types of probing on the SP. 

5 Enter the IP address for the probe target in the Probe Target (IP Address) field. The Probe IP 

address is a static IP address on the WAN. If this field is left blank, or 0.0.0.0 is entered as the 
address, the Probe Target is the WAN Gateway IP address. 

Note: The probe is a ping sent to the specified IP address to determine Internet connectivity.

6 Select ICMP Probing or TCP Probing from the Probe Type options. If you select TCP Probing, 

enter the TCP port number in the TCP port field.

7 In the Probe Interval (seconds) field, enter the amount of time between probes to the Probe 

Target. The default value is 5 seconds. To deactivate the Probe Detection feature, enter 0 as the