hostname RouterA


username RouterB password 7 246824
chat-script backup "" "AT" TIMEOUT 30 OK "ATDT 1234" TIMEOUT 30 CONNECT \c


interface Serial0
ip address 131.108.199.1 255.255.255.0
ip ospf cost 1562
bandwidth 1200
pulse-time 1


interface Async1
ip address 131.108.198.3 255.255.255.0
encapsulation ppp
async default ip address 131.108.198.4
async dynamic address
async dynamic routing
async mode dedicated
dialer in-band
dialer idle-timeout 200
dialer wait-for-carrier-time 120
dialer map IP 131.108.198.4 name RouterB modem-script backup 5678
dialer-group 1
ppp authentication chap


router igrp 110
network 131.108.0.0
neighbor 131.108.198.4
!^^^^^^^^
!  Use this, static routes, or broadcast maps


ip route 198.92.99.0 255.255.255.0 131.108.198.4 150
! ^^^^^^^^^^
! Floating static route to initiate DDR


access-list 101 deny   igrp 0.0.0.0 255.255.255.255 0.0.0.0 255.255.255.255
access-list 101 permit ip 0.0.0.0 255.255.255.255 0.0.0.0 255.255.255.255


dialer-list 1 list 101


line con 0
line aux 0
modem InOut
rxspeed 38400
txspeed 38400

hostname RouterB


username RouterA password 7 987654


interface Serial0
ip address 131.108.199.2 255.255.255.0
clockrate 64000
pulse-time 1


interface Async1
ip address 131.108.198.4 255.255.255.0
encapsulation ppp
async default ip address 131.108.198.3
async dynamic address
async dynamic routing
async mode dedicated
dialer in-band
dialer idle-timeout 200
dialer map IP 131.108.198.3 name RouterA
dialer-group 1
ppp authentication chap


router igrp 110
network 131.108.0.0
network 198.92.99.0


dialer-list 1 protocol ip permit


line con 0
line aux 0
password ww
login
modem InOut
rxspeed 38400
txspeed 38400

interface async 1
ip unnumbered ether 0
async default ip address x.x.x.x (generally, an address on eth0's net)
async mode interactive          (allows dial-in to start PPP/SLIP)
dialer string XXX               (XXX is the phone number)
dialer-group 1                  (filters what causes dialing)
...
dialer-list 1 proto ip permit   (any IP causes dialing)
...
line 1
modem inout
flow hard                       (HW flow control recommended)
login                           (for our login users)
password SECRET
modem chat-script dial-hayes    (how to dial on outbound on this line)
...
chat-script dial-hayes "" AT OK ATDT\T TIMEOUT 300 Password: SECRET2 > slip SLIP
...
ip route y.y.y.y async1         (y.y.y.y is the guy you dial up)
...
router igrp 109                 (if you're running a routing protocol...)
passive-interface async 1       (usually no route updates out async)
redistribute static             (advertise the y.y.y.y route to the net)