1.4. Installing NetworkManager

NetworkManager is installed by default on Red Hat Enterprise Linux. If necessary, to ensure that it is, enter the following command as the root user:
~]# yum install NetworkManager
For information on user privileges and gaining privileges, see the Red Hat Enterprise Linux System Administrator's Guide.

1.4.1. The NetworkManager Daemon

The NetworkManager daemon runs with root privileges and is, by default, configured to start up at boot time. You can determine whether the NetworkManager daemon is running by entering this command:
~]$ systemctl status NetworkManager
NetworkManager.service - Network Manager
   Loaded: loaded (/lib/systemd/system/NetworkManager.service; enabled)
   Active: active (running) since Fri, 08 Mar 2013 12:50:04 +0100; 3 days ago
The systemctl status command will report NetworkManager as Active: inactive (dead) if the NetworkManager service is not running. To start it for the current session enter the following command as the root user:
~]# systemctl start NetworkManager
Run the systemctl enable command to ensure that NetworkManager starts up every time the system boots:
~]# systemctl enable NetworkManager
For more information on starting, stopping and managing services, see the Red Hat Enterprise Linux System Administrator's Guide.

1.4.2. Interacting with NetworkManager

Users do not interact with the NetworkManager system service directly. Instead, users perform network configuration tasks using graphical and command-line user interface tools. The following tools are available in Red Hat Enterprise Linux 7:
  1. A simple curses-based text user interface (TUI) for NetworkManager, nmtui, is available.
  2. A command-line tool, nmcli, is provided to allow users and scripts to interact with NetworkManager. Note that nmcli can be used on systems without a GUI such as servers to control all aspects of NetworkManager. It is on an equal footing with the GUI tools.
  3. The GNOME Shell also provides a network icon in its Notification Area representing network connection states as reported by NetworkManager. The icon has multiple states that serve as visual indicators for the type of connection you are currently using.
  4. A graphical user interface tool called control-center, provided by the GNOME Shell, is available for desktop users. It incorporates a Network settings tool. To start it, press the Super key to enter the Activities Overview, type control network and then press Enter. The Super key appears in a variety of guises, depending on the keyboard and other hardware, but often as either the Windows or Command key, and typically to the left of the Space key.
  5. A graphical user interface tool, nm-connection-editor, is available for certain tasks not yet handled by control-center. To start it, press the Super key to enter the Activities Overview, type network connections or nm-connection-editor and then press Enter.
Network connection icon states

Figure 1.1. Network connection icon states