Попробуй вот так.
Если не будет работать то покажи sh diag
ip name-server днс провайдера
ip name-server днс провайдера
interface ATM0
no ip address
no ip redirects
no ip unreachables
no ip proxy-arp
ip route-cache flow
no atm ilmi-keepalive
dsl operating-mode auto
interface ATM0.1 point-to-point
no snmp trap link-status
0/33
encapsulation aal5snap
protocol ppp dialer
dialer pool-member 1
interface Dialer0
ip address negotiated
no ip redirects
no ip unreachables
no ip proxy-arp
ip nat outside
ip virtual-reassembly
encapsulation ppp
ip route-cache flow
dialer pool 1
dialer-group 1
no cdp enable
ppp authentication chap pap callin
ppp chap hostname xxxxxxx@axxxxx.xxxx
ppp chap password xxxxxxxxxxx
ppp pap sent-username xxxxxxx@axxxxx.xxxx password xxxxxxxxxxx
ip route 0.0.0.0 0.0.0.0 Dialer0
ip nat inside source list 1 interface Dialer0 overload
interface Vlan1
ip address первый реальний из пула(не броадкаст)
no ip redirects
no ip unreachables
no ip proxy-arp
ip virtual-reassembly
ip route-cache flow
ip tcp adjust-mss 1452