Задача состояла в следующем:

Есть циска 2610 + модем. Нужно обеспечить доступ локальной сети в internet по dialup`у. Циска должна звонить в инет при возникновени соответствующего трафика и разрывать соединение при его отсутствии

Предложено решение: использовать DDR+NAT

!
version 12.0
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname Router
!
enable secret 5 ****
!
!
!
memory-size iomem 10
ip subnet-zero
no ip domain-lookup
ip host modem 2002 10.0.0.1
!
!
!
voice-port 1/0/0
!
voice-port 1/0/1
!
voice-port 1/1/0
!
voice-port 1/1/1
!
process-max-time 200
!
interface Ethernet0/0
 ip address 10.0.0.1 255.255.255.0
 no ip directed-broadcast
 ip nat inside
!
interface Serial0/0
 no ip address
 no ip directed-broadcast
 shutdown
!
interface Serial0/1
 physical-layer async
 ip address negotiated
 no ip directed-broadcast
 ip nat outside
 encapsulation ppp
 dialer in-band
 dialer string P9955555
 dialer-group 1
 async mode interactive
 no fair-queue
 no cdp enable
 ppp authentication pap callin
 ppp pap sent-username guest password mtu

!
interface Serial0/2
 no ip address
 no ip directed-broadcast
 shutdown
!
interface Serial0/3
 no ip address
 no ip directed-broadcast
 shutdown
!
ip nat inside source list 100 interface Serial0/1 overload
ip classless
ip route 0.0.0.0 0.0.0.0 Serial0/1
no ip http server
!
access-list 100 permit ip any any
dialer-list 1 protocol ip permit
!
!
line con 0
 transport input none
line 2
 autoselect ppp
 modem InOut
 modem autoconfigure type codex_3260
 transport input telnet
 transport output none
 stopbits 1
 speed 38400
 flowcontrol hardware
line aux 0
line vty 0 4
 exec-timeout 0 0
 password ****
 login
!
!
end