Using Dialer Watch

Problem

You want to use Cisco’s Dialer Watch feature to trigger dial backup.

Solution

The Dialer Watch feature allows the router to track a particular destination IP address in its routing table. If all of the tracked IP addresses disappear from the routing table, the router automatically triggers the dial backup connection:

Router1#configure terminal 
Enter configuration commands, one per line.  End with CNTL/Z.
Router1(config)#interface BRI0/0
Router1(config-if)#ip address 10.1.99.55 255.255.255.0
Router1(config-if)#encapsulation ppp
Router1(config-if)#dialer map ip 10.1.1.0 name dialhost broadcast 95551212
Router1(config-if)#dialer map ip 10.2.0.0 name dialhost broadcast 95551212
Router1(config-if)#dialer map ip 10.1.99.1 name dialhost broadcast 95551212
Router1(config-if)#dialer load-threshold 50 either
Router1(config-if)#dialer watch-group 1
Router1(config-if)#dialer-group 1
Router1(config-if)#isdn switch-type basic-ni
Router1(config-if)#isdn spid1 800555123400 5551234
Router1(config-if)#isdn spid2 800555123500 5551235
Router1(config-if)#ppp authentication chap
Router1(config-if)#ppp multilink
Router1(config-if)#exit
Router1(config)#router eigrp 55
Router1(config-router)#network 10.0.0.0
Router1(config-router)#exit
Router1(config)#username dialhost password cisco
Router1(config)#access-list 101 deny eigrp any any
Router1(config)#access-list 101 permit ip any any
Router1(config)#dialer-list 1 protocol ip list 101
Router1(config)#dialer watch-list 1 ip 10.2.0.0 ...

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