don't know which version of kppp you are running. Maybe you hit one
of the problems discussed in /usr/share/doc/kppp/README.Debian:
kppp and execution of kppp
In order to actually use kppp you must first be a part of the "dip" group.
This is the same for using PPP in general on Debian. If you are not a part
of this group you will not be able to actually run pppd or setup proper
kppp and immediate disconnects
In order for kppp to properly work you must set "noauth" in /etc/ppp/options.
Keep in mind that you main have /etc/ppp/options.ttyS0 (For example) so make
sure you change it in the proper (all?) file.
The default is "auth" so if you don't change this most likely you'll connect
and end up just getting a disconnect shortly after.
- From: Robin Gerard <firstname.lastname@example.org>