In my knoppix 3.5 HD install /etc/sysconfig/provider directory there are 3 files The one that's accessable to group has this in it:

PROVIDER="Telia Internett (.com)"
USER="test"
PASSWORD="test"
ENCAP="syncppp"
DIALMODE="manual"
SECURE="off"
MSN="0"
PHONE_IN=""
AREACODE=""
PHONE_OUT="52049007"
BUNDLING="off"
LOCAL_IP=""
REMOTE_IP=""
HUPTIMEOUT="360"
DNS="10.0.0.1"
DOMAIN="telia.com"
CALLBACK="off"
CHARGEHUP=""
CHARGEINT=""
CBHUP=""
CBDELAY="3"
DIALMAX=""
AUTH="+pap -chap"
IHUP=""
DELDEFAULTROUTE="enabled"

I usually believe that /etc/ppp has the most troublesome files when there is a problem.
What did you use to configure your internet connection? I believe the preferred method is to do "pppconfig" in a shell.