NetworkManager attempts to keep an active network connection available at all times.
NetworkManager is composed of two parts:
A daemon running as root (network-manager).
NetworkManager will only handle interfaces not declared in /etc/network/interfaces (see README file).
The features of NetworkManager are described on its homepage.
Make sure you read the fine manual:
interfaces(5) man page
- Q. How do I configure a static IP address (for a server, etc) ?
A) Configure /etc/network/interfaces.
- Q. Why can't I see NetworkManager with my new user account ?
A) Make sure human users are in the netdev group (see /usr/share/doc/network-manager-gnome/README.Debian).
http://www.gnome.org/projects/NetworkManager/ - Project homepage and GNOME front-end;
http://en.opensuse.org/Projects/KNetworkManager - KDE front-end
http://vidner.net/martin/software/cnetworkmanager/ - Command line interface