ppp problems

[yellowdog-general@lists.terrasoftsolutions.com]

I connect to the internet via ppp with kppp. I' have no problem getting 
connect, but I can't navigate if the ethernet port is on. Once I 
deactivate 
my ethernet port I can surf the web. As soon as I switch it on, Mozilla 
can't 
resolve any address. I understand my computer try to access the web via 
the 
ethernet port (if on) and not with the active ppp connection. How can I 
solve 
this ?

thanks for help,

Andrea