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I'm based in the UK, and we have recently acquired VDSL FTTC Fibre optic connection. We are currently using the provider supplied VDSL modem and wireless router.

We want to use our Cisco 877 instead of the wireless router. Apparently we can't get around using the supplied VDSL modem. I've found configs on the internet for how to do this, but I cannot seem to get it to work. Effectively we've configured the router to use FastEthernet3 for the WAN connection, which is also configured with the PPPoE settings required. We're going to use FastEthernet0 to connect to our internal LAN, with NAT configured on these two ports.

Has anyone had any success with this, or am I attempting something which is not possible?

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up vote 1 down vote accepted

I've finally got it to work, here are the sections of my config which did it:

interface ATM0
 no ip address
 no atm ilmi-keepalive
 pvc 0/38 
  encapsulation aal5mux ppp dialer

interface FastEthernet0
interface FastEthernet1
interface FastEthernet2
 switchport access vlan 101
interface FastEthernet3
interface Vlan1
 ip address
 ip nat inside
 ip virtual-reassembly
 zone-member security in-zone
interface Vlan101
 no ip address
 no ip redirects
 no ip unreachables
 no ip proxy-arp
 ip virtual-reassembly
 pppoe enable group global
 pppoe-client dial-pool-number 1
interface Dialer1
 description $FW_OUTSIDE$
 mtu 1492
 ip address negotiated
 no ip unreachables
 ip nat outside
 ip virtual-reassembly
 zone-member security out-zone
 encapsulation ppp
 dialer pool 1
 dialer-group 1
 no cdp enable
 ppp chap hostname 
 ppp chap password 0 
 ppp ipcp route default
ip forward-protocol nd
ip http server
ip http authentication local
ip http secure-server
ip http timeout-policy idle 60 life 86400 requests 10000
ip nat inside source list 1 interface Dialer1 overload
ip access-list extended NAT
 permit ip any
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