Undoing changes by pppoeconf

I just got my new Dell with Ubuntu and thought I needed to configure something to get my new DSL service up and running so I ran pppoeconf. (It turns out I needed to register with ATT first. See my previous post.) So I needed to undo the changes I made with pppoeconf. Googling around a little, it appears there is no undo command for pppoeconf. However, I found the key configuration file was: /etc/network/interfaces. I looked at it, but wasn't sure which stuff to delete. I popped in my Ubuntu live installation disk (included with my Dell). Using the live CD, the internet worked great. So I looked at the /etc/network/interfaces while using the live CD and then edited my installed version to match.

Here is what my /etc/network/interfaces file looked like after running pppoeconf:

auto lo
iface lo inet loopback


auto dsl-provider
iface dsl-provider inet ppp
pre-up /sbin/ifconfig eth0 up # line maintained by pppoeconf
provider dsl-provider

auto eth0
iface eth0 inet manual

Here is the default /etc/network/interfaces on Ubuntu 7.10 Gutsy (only two lines):

auto lo
iface lo inet loopback