"Выкушено" отсюда:
http://www.cisco.com/en/US/docs/routers/access/800/860-880-8...interface Cellular0
ip nat outside
ip virtual-reassembly
interface Vlan1
ip address 10.4.0.254 255.255.0.0
ip nat inside
ip virtual-reassembly
interface Dialer2
ip address negotiated
ip nat outside
ip virtual-reassembly
ip local policy route-map track-primary-if
ip forward-protocol nd
ip route 0.0.0.0 0.0.0.0 Dialer2 track 234
ip route 0.0.0.0 0.0.0.0 Cellular0 254
ip nat inside source route-map nat2cell interface Cellular0 overload
ip nat inside source route-map nat2dsl interface Dialer2 overload
!
ip sla 1
icmp-echo 209.131.36.158 source-interface Dialer2
timeout 1000
frequency 2
ip sla schedule 1 life forever start-time now
access-list 101 permit ip 10.4.0.0 0.0.255.255 any
access-list 102 permit icmp any host 209.131.36.158
access-list 103 permit ip host 166.136.225.89 128.107.0.0 0.0.255.255
access-list 103 permit ip host 75.40.113.246 128.107.0.0 0.0.255.255
route-map track-primary-if permit 10
match ip address 102
set interface Dialer2
!
route-map nat2dsl permit 10
match ip address 101
match interface Dialer2
!
route-map nat2cell permit 10
match ip address 101
match interface Cellular0