TravelingPacket – A blog of network musings

I would say no one will find this useful, but I have DSL at home .. I know. The following config is how to add a Cisco router use AT&T DSL. I have done this many times but not in the last two years or so, I had trouble finding good documentation on google for exactly what I needed to do, so I thought I would share.

The main parts of the config needed are creating a dialer interface, setting the authentication and user/pass. Then associating that dialer interface with your Physical Ethernet interface, and lastly configuring the default route.

First lets configure the Dialer Interface

config t

interface Dialer1
ip address negotiated
ip mtu 1492
ip nat outside
encapsulation ppp
ip tcp adjust-mss 1460
dialer pool 1
dialer-group 1
ppp authentication chap pap callin optional
ppp chap hostname username@att.net
ppp chap password password
ppp pap sent-username username@att.net password password

Now lets associate that with a real interface:

interface FastEthernet0/1
no ip address
duplex auto
speed auto
pppoe enable group global
pppoe-client dial-pool-number 1
!

Next lets set our default route and point it out of the Dialer interface

ip route 0.0.0.0 0.0.0.0 Dialer1

Given we have all our user/pass correct in a minute you should be able to do a “Show IP int br” and see the ip address passed to us by our ATT DSL Modem in bridge mode on the dialer interface.