Yon only need to configure HSRP for your LAN interface. You can setup your R1 WAN router as primary hsrp router. As well as that, configure the R1 HSRP to track your WAN interface.
If R1 WAN interface was down, it would reduce the HSRP priority, so the R2 backup isdn router can take over as default gateway and route traffic via ISDN connection.
If R1 WAN interface and R2 router were down at the sametime. R1 remain as default gateway router and route traffic via ISDN connection using floting static route.
hope this helps....
sample config.
ISDN-R1
********
!
interface FastEthernet0/0
description - PRIMARY LAN INTERFACE -
ip address 10.10.10.2 255.255.255.0
speed 100
full-duplex
standby 10 ip 10.10.10.1
standby 10 priority 150
standby 10 preempt
standby 10 track Serial1/0.103 80
!
interface Serial1/0
no ip address
encapsulation frame-relay
serial restart-delay 0
no frame-relay inverse-arp
!
interface Serial1/0.103 point-to-point
description - FR WAN Connection -
ip address 20.x.x.1 255.255.255.0
frame-relay interface-dlci 103
!
interface bri 0
encapsulation PPP
dialer pool-member 1
!
interface dialer0
ip 30.x.x.1 255.255.255.0
encapsulation ppp
dialer remote-name Remote-Router
dialer pool 1
dialer string 5551212
dialer-group 1
!
ip route 0.0.0.0 0.0.0.0 Serial1/0.103
ip route 0.0.0.0 0.0.0.0 dialer0 100
!
ISDN-R2
********
!
interface FastEthernet0/0
description - SECONDARY LAN INTERFACE -
ip address 10.10.10.3 255.255.255.0
speed 100
full-duplex
standby 10 ip 10.10.10.1
standby 10 preempt
!
!
interface bri 0
encapsulation PPP
dialer pool-member 1
!
interface dialer0
ip 40.x.x.1 255.255.255.0
encapsulation ppp
dialer remote-name Remote-Router
dialer pool 1
dialer string 5551212
dialer-group 1
!
!
ip route 0.0.0.0 0.0.0.0 dialer0
!
regards,
eng siong
