! Listing 6.12: North Router using dialer watch to control backup ISDN link
!
!Copyright (C) 2001 by Vincent C Jones. All Rights Reserved.


version 12.0
!
hostname North
! Router with ISDN backup link
username DataCenter password SharedSecret
!
interface Ethernet0
 ip address 10.101.5.2 255.255.255.0
!
interface BRI0
! Secondary backup line
 ip address 10.2.1.5 255.255.0.0
 encapsulation ppp
! Dialer map for the IP network which is being watched
 dialer map ip 10.1.0.0 name DataCenter speed 56 broadcast 18005551212 
! Dialer map for the actual remote end address for routing
 dialer map ip 10.2.255.254 name DataCenter speed 56 broadcast 18005551212
 dialer-group 1
! Enable dialer watch on this interface
 dialer watch-group 2
 ppp authentication chap
!
! Must use EIGRP or IGRP routing for dialer watch
router eigrp 1
 network 10.0.0.0
 no auto-summary
!
access-list 100 deny   eigrp any any
access-list 100 permit ip any any
! Watch IP network 10.1.0.0
dialer watch-list 2 ip 10.1.0.0 255.255.0.0
dialer-list 1 protocol ip list 100
!
end