Network Manager is a great tool to manage internet connection and it is integrated well with gnome, but it only works with certain devices. For obscure devices like some CDMA modems, we must use KPPP|Gnome-PPP or the more powerful yet GUI-less wvdial.
For instance Nokia 6255 CDMA phone | modem, for some reason(s) it won't connect with Network Manager, and I have to use wvdial or gnome-ppp or kppp.
Although it connects with gnome-ppp, there's a bug(?) that make it won't share internet connection (either via ethernet nor wi-fi). The fix? Connect the shared connection before you make the internet connection via gnome-ppp. That's it.
Although I use Gnome, I use and like KPPP better than Gnome-PPP :)
keyword : gnome-ppp | kppp | wvdial | share internet | problem