Networking question

[Jonathan Jefferies]

Got a problem with my networking.  I'm running
slink on a K6 machine with 64 megs, connected
by ether net to another linux box and my wife's
win95 machine.  Only connection to the web was
ppp dialup to isp.  Started to install the
debian packages which handle dns, contains
"named" and some other routines.  Decided it
made more sense to use the isp's dns servers
and uninstalled the just installed package.

Problem is that the process somehow disturbed
something.  Symptom is that when I make a
ppp connection - using wvdial - I cannot
ping outside of my computer. The error message
is that the "operation is not permitted".
I've about decided this is due to the scripts
which call ifconfig and route being broken.
After booting if I try pinging local host,
127.0.0.1, it fails with the same error message.
Only if I establish an interface using ifconfig and 
then route, can I can ping it. So
the scripts to call ifconfig and route at
boot time are probably broken.  But with a PPP
link established - I can see it using netstat -
as default I still cannot ping outside
my machine.  My current thought is that
?? /etc/ppp/ip-up (can't remember the whole filename)
must have been broken.  But I've not been
able to locate documentation as to what the
contents of this file should be and how they
should be setup so that the dns servers I point
to in /etc/hosts can be accessed.  I've been
going through the linux networking book and
HOWTO's and FAQS but haven't found the magic
key.  

Would anyone have a suggestion as to
what my problem is or where I should be looking.

thanks
J.