Chapter 35. Using NetworkManager

Chapter 35. Using NetworkManager¶

Contents

35.1. Use Cases for NetworkManager
35.2. Enabling NetworkManager
35.3. Configuring Network Connections
35.4. Using KNetworkManager
35.5. Using GNOME NetworkManager Applet
35.6. NetworkManager and VPN
35.7. NetworkManager and Security
35.8. Frequently Asked Questions
35.9. Troubleshooting
35.10. For More Information

NetworkManager is the ideal solution for laptops and other portable computers. It supports state-of-the-art encryption types and standards for network connections, including connections to 802.1X protected networks. 802.1X is the “IEEE Standard for Local and Metropolitan Area Networks—Port-Based Network Access Control”. With NetworkManager, you do not need to worry about configuring network interfaces and switching between wired or wireless networks when you are moving. NetworkManager can automatically connect to known wireless networks or manage several network connections in parallel—the fastest connection is then used as default. Furthermore, you can manually switch between available networks and manage your network connection using an applet in the system tray.

Instead of only one connection being active, multiple connections may be active at once. This enables you to unplug your laptop from an Ethernet and remain connected via a wireless connection.

35.1. Use Cases for NetworkManager¶

NetworkManager provides a sophisticated and intuitive user interface, which enables users to easily switch their network environment. However, NetworkManager is not a suitable solution in the following cases:

Your computer provides network services for other computers in your network, for example, it is a DHCP or DNS server.
Your computer is a Xen server or your system is a virtual system inside Xen.

35.2. Enabling NetworkManager¶

On laptop computers, NetworkManager is enabled by default. However, it can be at any time enabled or disabled in the YaST Network Settings module.

Run YaST and go to Network Devices+Network Settings.
The Network Settings dialog opens. Go to the Global Options tab.
To configure and manage your network connections with NetworkManager, select User Controlled with NetworkManager.
Click OK.
After choosing the method for managing network connections, set up your network card using automatic configuration via DHCP or a static IP address or configure your modem (for dial-up connections, use Network Devices+Modem). To configure an internal or USB ISDN modem, select Network Devices+ISDN. To configure an internal or USB DSL modem, select Network Devices+DSL.
Find a detailed description of the network configuration with YaST in Section 23.4, “Configuring a Network Connection with YaST” and Chapter 34, Wireless LAN.

After having enabled NetworkManager, configure your network connections with the NetworkManager as described in Section 35.3, “Configuring Network Connections”.

If you want to deactivate NetworkManager and control network the traditional way, choose the Traditional Method with ifup option in the Network Setup Method field.

35.3. Configuring Network Connections¶

After having enabled NetworkManager in YaST, configure your network connections with the NetworkManager front-ends available in KDE and GNOME. The network configuration dialogs for both front-ends are very similar. They show tabs for all types of network connections, such as wired, wireless, mobile broadband, DSL, and VPN connections. On each tab, you can add, edit or delete connections of that type. In the KDE configuration dialog, the appropriate tabs are only active if the connection type is available on your system (depending on hardware and software). By default, KNetworkManager also displays comprehensive tooltips for the input fields and options available on each tab.

	Bluetooth Connections
At the moment, Bluetooth connections cannot be configured with NetworkManager.

To open the network configuration dialog in GNOME, open the main menu and click the Network entry at the right. Alternatively, press +F2 and enter nm-connection-editor or select Hardware+Network Connections in the GNOME Control Center.

Figure 35.1. GNOME Network Connections Dialog

If you use KDE, open the main menu and click System settings. In the Network and Connectivity section select Network Settings+Network Connections to open the network configuration dialog. Alternatively, press +F2 and enter kcm_networkmanagement or .

Figure 35.2. KDE Network Configuration Dialog

Alternatively, you can also start the configuration dialogs from the NetworkManager applet in the system tray. In KDE, left-click the icon and select Manage Connections. In GNOME, right-click the icon and select Edit Connections.

	Availability of Options
Depending on your system set-up, you may not be allowed to configure connections. In a secured environment, some options might be locked or require `root` permission. Ask your system administrator for details.

Procedure 35.1. Adding or Editing Connections¶

When configuring network connections with NetworkManager, you can also define system connections that can be shared by all users. In contrast to user connections, system connections are made available right after NetworkManager is started—before any users log in. For more details about both types of connections, refer to Section 35.7.1, “User and System Connections”.

Currently, the system connection option is not available in KDE. To set up system connections, you need to use YaST in this case.

	Hidden Networks
To connect to a “hidden” network (a network that does not broadcast its service) you have to know the Service Set Identifier or Extended Service Set Identifier (SSID or ESSID) of the network because it cannot be detected automatically.

To add a new connection or edit an existing one, click the tab for the connection type you want to use and click Add or choose an existing connection and click Edit.
Enter a Connection Name and your connection details.
You can tie the connection to a certain device, if more than one physical device per connection type is available (for example, your machine is equipped with two ethernet cards or two wireless cards).
If you use KDE, do so by using the Restrict to Interface option. If you use GNOME, enter the MAC address of the device you want to tie the connection to and confirm your settings.
If you want NetworkManager to automatically use a certain connection, activate Connect Automatically for this connection.
To turn a connection into a system connection activate Available to all users (GNOME). To create and edit system connections, root permission is required.

After having confirmed your changes, the newly configured network connection appears in the list of available networks you get by left-clicking the NetworkManager applet.

Figure 35.3. KNetworkManager—Configured and Available Connections

35.4. Using KNetworkManager¶

The KDE front-end for NetworkManager is the NetworkManager plasmoid. If the network has been set up for NetworkManager control, the plasmoid usually starts automatically with the desktop environment and is shown as an icon in the system tray.

If your system tray does not show any network connection icon, the plasmoid is probably not started. Click on the Panel Tool Box and choose Add Widgets. Double-click on the Network Management entry and click on the Panel Tool Box again.

The NetworkManager front-end only shows wireless networks for which you have configured a connection. It hides connections when you are out of range of a wireless network, or when the network cable is disconnected, thus always giving you a clear view of which connections may be used.

35.4.1. Managing Wired Network Connections¶

If your computer is connected to an existing network with a network cable, use the NetworkManager front-end to manage the network connection(s).

Left-click the NetworkManager icon to show a menu with available Connections and Interfaces. Connections are being displayed in the right half of the plasmoid window, while interfaces show up in the left half. The connection and interface currently being used is marked with a blue globe.
Click on Networking Interface listed in the right half of the plasmoid window to get detailed information and statistics for that interface. Switch back to the interface overview by clicking on the blue arrow icon.
To disconnect an active connection, click on the red icon for the Networking Interface in the right half of the plasmoid window.
If you want to use a different configuration with the wired network, click Manage Connections and add another wired connection as described in Procedure 35.1, “Adding or Editing Connections”. Click the NetworkManager icon and select the newly configured connection to activate it.
To switch off all network connections, both wired and wireless, click the NetworkManager icon and uncheck Enable Networking.

35.4.2. Managing Wireless Network Connections¶

By default the NetworkManager frontend only lists connections that are already configured. The signal strength of each network is indicated by a series of bars, each one representing 10%. Encrypted wireless networks are marked with a green (WPA) or yellow (WEP) shield, while open networks are marked with a red shield.

Procedure 35.2. Connecting to a Wireless Network

Click Show More to display all visible wireless networks available.
Left-click on the network of your choice to open the network connection dialog. To connect to a network that does not broadcast its service set identifier ((E)SSID), click on hidden network and press . Fill in the connection details and proceed with OK.
Based on your security settings for NetworkManager (see Section 35.7.2, “Storing Passwords and Credentials” for details), you may have to provide your KWallet password.
NetworkManager automatically connects to the configured network.

Procedure 35.3. Managing Active Wireless Connections

Click on WLAN Interface listed in the right half of the plasmoid window to get detailed information and statistics for that interface. Switch back to the interface overview by clicking on the blue arrow icon.
To disconnect an active connection, click on the red icon for the WLAN Interface.
To completely disable wireless networking, uncheck Enable Wireless. This can be useful if you are on a plane or in any other environment where wireless networking is not allowed.

A wireless network that has been chosen explicitly will remain connected as long as possible. If a network cable is plugged in during that time, any connections that have been set to Connect Automatically will be connected, while the wireless connection remains up.

35.4.3. Configuring Your Wireless Card as an Access Point¶

If your wireless card supports access point mode, you can use NetworkManager for configuration.

	Availability of Options
Depending on your system set-up, you may not be allowed to configure connections. In a secured environment, some options might be locked or require `root` permission. Ask your system administrator for details.

Start the dialog for configuring network connections as described in Section 35.3, “Configuring Network Connections” and Add a Wireless connection.
On the Wireless tab provide a Connection name and an SSID. Set Method+Ad-hoc.

Set the encryption on the Wireless Security tab.

	Unprotected Wireless Networks Are a Security Risk
If you set Security to `None`, everybody can connect to your network, reuse your connectivity and intercept your network connection. To restrict access to your access point and to secure your connection, use encryption. You can choose between various WEP and WPA–based encryptions. If you are not sure which technology is best for you, read Section 34.3, “Authentication”.

On the IP Address tab, make sure the Method option is set to Shared.
Confirm your configuration with OK.

35.5. Using GNOME NetworkManager Applet¶

In GNOME, NetworkManager can be controlled with the GNOME NetworkManager applet. If the network is set up for NetworkManager control, the applet usually starts automatically with the desktop environment and is shown as an icon in the system tray.

If your system tray does not show any network connection icon, the applet is probably not started. Press +F2 and enter nm-applet to start it manually.

35.5.1. Managing Wired Network Connections¶

If your computer is connected to an existing network with a network cable, use the NetworkManager applet to choose the network connection.

Left-click the applet icon to show a menu with available networks. The currently used connection is listed on top of the menu, followed by other active connections. Inactive connections are listed under Available.
Right-click the applet and choose Connection Information to get detailed information on all active interfaces.
To disconnect an active connection, left-click the applet and choose its Disconnect entry.
If you want to use a different configuration with the wired network, right-click the applet, choose Edit Connections and add another wired connection as described in Procedure 35.1, “Adding or Editing Connections”. Click the NetworkManager icon and select the newly configured connection to activate it.
To switch off all network connections, both wired and wireless, right-click the applet icon and uncheck Enable Networking.

35.5.2. Managing Wireless Network Connections¶

Available visible wireless networks are listed in the GNOME NetworkManager applet menu under Available and More Networks. The signal strength of each network is also shown in the menu. Encrypted wireless networks are marked with a lock icon.

Procedure 35.4. Connecting to a Wireless Network

To connect to a wireless network, left-click the applet icon and choose an entry from the list of available wireless networks.
If the network is encrypted, a dialog opens. It shows the type of encryption the network uses (Wireless Security) and holds a number of input fields according to the respective encryption and authentication settings. Enter the appropriate credentials.
To connect to a network that does not broadcast its service set identifier ((E)SSID) and therefore cannot be detected automatically, left-click the NetworkManager icon and choose Connect to Hidden Wireless Network.
In the dialog that opens, enter the ESSID and set encryption parameters on the Wireless Security tab if necessary.
To disable wireless networking, right-click the applet icon and uncheck Enable Wireless. This can be useful if you are on a plane or in any other environment where wireless networking is not allowed.

35.5.3. Configuring Your Wireless Card as an Access Point¶

If your wireless card supports access point mode, you can use NetworkManager for configuration.

	Availability of Options
Depending on your system set-up, you may not be allowed to configure connections. In a secured environment, some options might be locked or require `root` permission. Ask your system administrator for details.

Click the NetworkManager applet and select Create New Wireless Network.

Enter a Network Name and set the encryption to use with the Wireless Security drop-down list.

	Unprotected Wireless Networks Are a Security Risk
If you set Wireless Security to `None`, everybody can connect to your network, reuse your connectivity and intercept your network connection. To restrict access to your access point and to secure your connection, use encryption. You can choose between various WEP and WPA–based encryptions. If you are not sure which technology is best for you, read Section 34.3, “Authentication”.

35.6. NetworkManager and VPN¶

NetworkManager supports several Virtual Private Network (VPN) technologies. For each technology, openSUSE comes with a base package providing the generic support for NetworkManager. In addition to that, you also need to install the respective desktop-specific package for your applet.

NovellVPN

To use this VPN technology, install

NetworkManager-novellvpn and
NetworkManager-novellvpn-gnome.

NovellVPN support for KDE is not available yet, but is currently being worked on.

OpenVPN

To use this VPN technology, install

NetworkManager-openvpn and
NetworkManager-openvpn-kde4 or NetworkManager-openvpn-gnome.

vpnc (Cisco)

To use this VPN technology, install

NetworkManager-vpnc and
NetworkManager-vpnc-kde4 or NetworkManager-vpnc-gnome.

PPTP (Point-to-Point Tunneling Protocol)

To use this VPN technology, install

NetworkManager-pptp and
NetworkManager-pptp-kde4 or NetworkManager-pptp-gnome.

After you have installed the packages, configure your VPN connection as described in Section 35.3, “Configuring Network Connections”.

35.7. NetworkManager and Security¶

NetworkManager distinguishes two types of wireless connections, trusted and untrusted. A trusted connection is any network that you explicitly selected in the past. All others are untrusted. Trusted connections are identified by the name and MAC address of the access point. Using the MAC address ensures that you cannot use a different access point with the name of your trusted connection.

NetworkManager periodically scans for available wireless networks. If multiple trusted networks are found, the most recently used is automatically selected. NetworkManager waits for your selection in case that all networks are untrusted.

If the encryption setting changes but the name and MAC address remain the same, NetworkManager attempts to connect, but first you are asked to confirm the new encryption settings and provide any updates, such as a new key.

If you switch from using a wireless connection to offline mode, NetworkManager blanks the ESSID. This ensures that the card is disconnected.

35.7.1. User and System Connections¶

NetworkManager knows two types of connections: user and system connections. User connections are connections that become available to NetworkManager when the first user logs in. Any required credentials are asked from the user and when the user logs out, the connections are disconnected and removed from NetworkManager. Connections that are defined as system connection can be shared by all users and are made available right after NetworkManager is started—before any users log in. In case of system connections, all credentials must be provided at the time the connection is created. Such system connections can be used to automatically connect to networks that require authorization. For information how to configure user or system connections with NetworkManager, refer to Section 35.3, “Configuring Network Connections”.

For KDE, configuring system connections with NetworkManager are currently not supported (use YaST instead).

35.7.2. Storing Passwords and Credentials¶

If you do not want to re-enter your credentials each time you want to connect to an encrypted network, you can use the desktop-specific tools GNOME Keyring Manager or KWalletManager to store your credentials encrypted on the disk, secured by a master password.

Under KDE, you can configure if and how to store your credentials. To do so, left-click the NetworkManager icon and select Manage Connections. Click Other+Connection Secrets and select one of the following options:

Do Not Store (Always Prompt)

This is useful if you are working in an environment where storing credentials is considered a security risk.

In File (Unencrypted)

If you choose this option, your passwords are stored unencrypted in the respective connection file that is created for each connection.

	Security Risk
Storing your network credentials unencrypted is a security risk. Everybody who has access to your computer can reuse your connectivity and intercept your network connection.

In Secure Storage (Encrypted)

If you choose this options, your credentials are stored in KWalletManager.

35.8. Frequently Asked Questions¶

In the following, find some frequently asked questions about configuring special network options with NetworkManager.

How to tie a connection to a specific device?

By default, connections in NetworkManager are device type-specific: they apply to all physical devices with the same type. If more than one physical device per connection type is available (for example, your machine is equipped with two ethernet cards), you can tie a connection to a certain device.

To do so in GNOME, first look up the MAC address of your device by using the output of the command line tool ifconfig). Then start the dialog for configuring network connections and choose the connection you want to modify. On the Wired or Wireless tab, enter the MAC Address of the device and confirm your changes.

If you use KDE, start the dialog for configuring network connections and choose the connection you want to modify. On the Ethernet or Wireless tab, use the Restrict to Interface option to select the network interface to which to tie the connection.

How to specify a certain access point in case multiple access points with the same ESSID are detected?

When multiple access points with different wireless bands (a/b/g/n) are available, the access point with the strongest signal is automatically chosen by default. To override this, use the BSSID field when configuring wireless connections.

The Basic Service Set Identifier (BSSID) uniquely identifies each Basic Service Set. In an infrastructure Basic Service Set, the BSSID is the MAC address of the wireless access point. In an independent (ad-hoc) Basic Service Set, the BSSID is a locally administered MAC address generated from a 46-bit random number.

Start the dialog for configuring network connections as described in Section 35.3, “Configuring Network Connections”. Choose the wireless connection you want to modify and click Edit. On the Wireless tab, enter the BSSID.

How to share network connections to other computers?

The primary device (the device which is connected to the Internet) does not need any special configuration. However, you need to configure the device that is connected to the local hub or machine as follows:

Start the dialog for configuring network connections as described in Section 35.3, “Configuring Network Connections”. Choose the connection you want to modify and click Edit. If you are using GNOME, switch to the IPv4 Settings tab and from the Method drop-down list, choose Shared to other computers. If you are using KDE, switch to the IP Address tab and from the Method drop-down list, choose Shared. That will enable IP traffic forwarding and run a DHCP server on the device. Confirm your changes in NetworkManager.
As the DCHP server uses port 67, make sure that it is not blocked by the firewall: On the machine sharing the connections, start YaST and select Security and Users+Firewall. Switch to the Allowed Services category. If DCHP Server is not already shown as Allowed Service, select DCHP Server from Services to Allow and click Add. Confirm your changes in YaST.

How to provide static DNS information with automatic (DHCP, PPP, VPN) addresses?

In case a DHCP server provides invalid DNS information (and/or routes), you can override it. Start the dialog for configuring network connections as described in Section 35.3, “Configuring Network Connections”. Choose the connection you want to modify and click Edit. If you are using GNOME, switch to the IPv4 Settings tab, and from the Method drop-down list, choose Automatic (DHCP) addresses only. If you are using KDE, switch to the IP Address tab, and from the Method drop-down list, choose Automatic (DHCP) addresses only. Enter the DNS information in the DNS Servers and Search Domains fields. From the drop-down list at the top of the tab, select Routes if you want to Ignore automatically obtained routes. Confirm your changes.

How to make NetworkManager connect to password protected networks before a user logs in?

Define a system connection that can be used for such purposes. For more information, refer to Section 35.7, “NetworkManager and Security”.

35.9. Troubleshooting¶

Connection problems can occur. Some common problems related to NetworkManager include the applet not starting or a missing VPN option. Methods for resolving and preventing these problems depend on the tool used.

NetworkManager Desktop Applet Does Not Start

The GNOME and KDE NetworkManager applets start automatically if the network is set up for NetworkManager control. If the applet does not start, check if NetworkManager is enabled in YaST as described in Section 35.2, “Enabling NetworkManager”. Then make sure that the appropriate package for your desktop environment is also installed. If you are using KDE 4, the package is plasmoid-networkmanagement. For GNOME users the package is NetworkManager-gnome.

If the desktop applet is installed but is not running for some reason, start it manually. Under GNOME press +F2 and enter nm-applet. Under KDE click on the Panel Tool Box and choose Add Widgets. Double-click on the Network Management entry and click on the Panel Tool Box again.

NetworkManager Applet Does Not Include the VPN Option

Support for NetworkManager, applets, and VPN for NetworkManager is distributed in separate packages. If your NetworkManager applet does not include the VPN option, check if the packages with NetworkManager support for your VPN technology are installed. For more information, see Section 35.6, “NetworkManager and VPN”.

No Network Connection Available

If you have configured your network connection correctly and all other components for the network connection (router, etc.) are also up and running, it sometimes helps to restart the network interfaces on your computer. To do so, log in to a command line as root and run rcnetwork restart.

35.10. For More Information¶

More information about NetworkManager can be found on the following Web sites and directories:

NetworkManager Project Page

http://projects.gnome.org/NetworkManager/

KDE NetworkManager Front-End

http://userbase.kde.org/NetworkManagement

Package Documentation

Also check out the information in the following directories for the latest information about NetworkManager and the GNOME and KDE NetworkManager applets:

/usr/share/doc/packages/NetworkManager/,
/usr/share/doc/packages/NetworkManager-gnome/.