NetworkManager, a tool for silent Linux Network Management

Applications such as Firefox and OpenOffice are all shining, because they can be seen and touched, and are the cornerstone applications of a free desktop. But are those programs that run quietly in the background and complete their work silently ignored unless they encounter bugs? NetworkManager is an important software that has never been praised, but is indispensable for Linux users.

What is NetworkManager?

NetworkManager consists of a management system network connection, a background service that reports its status through a D-BUS, and a client program that allows users to manage network connections. The original intention of developing NetworkManager is to simplify network connections so that the desktop itself and other applications can perceive the network.

Most users do not have to worry about the backend services of NetworkManager. They only manage network connections through the applets GUI. For GNOME and Xfce, It is the nm-applet tool, and for KDE users, it is KNetworkManager.

Many Linux users do not remember or even realize the kind of hard work and pain in managing network connections in early Linux. Especially for laptop users who need to connect to two or more networks. Although the earlier versions of NetworkManager were also difficult to use, at that time there was a nickname NetworkMangler, that is, a network grinder), but now it has become a powerful tool, make the management network no longer painful.

For example, I remember that when I loaded my Verizon Wireless EV-DO card into openSUSE 11.0 two years ago, NetworkManager didn't need any setup at all. It recognizes this card and appears in the drop-down menu of the GNOME toolbar. The only operation required is to click "Connect ". This is the simplest way to configure a wireless network card that I have encountered over the years.

However, there is always a need for improvement, so NetworkManager continues to develop. The upcoming version 0.8.1 can be found in Fedora 13, bringing a lot of improvements and new features.

New Functions of 0.8.1

The latest NetworkManager version includes many new features, most of which are related to supporting more network devices. Mobile users will like this version, because 0.8.1 has added support for mobile broadband devices such as GSM, UMTS, and CDMA cards. ModemManager also provides new functions, such as signal strength display and 2G/3G mode selection. In the end, you can also turn off the roaming function to avoid additional connection fees.

0.8.1 also supports the use of Bluetooth, which not only supports personal Regional Network (PAN) access, but also supports the old Bluetooth Dial-Up Network (DUN) protocol. All or most) supported devices can be found on the wiki.

If you are one of the few users who use IPv6, they swear that everyone will use it later), you will be happy to find that NetworkManager now supports IPv6 automatic configuration and static IP. Version 0.8.1 also provides IPv6 DHCP support.

Although most recent changes are supported by enhanced devices or protocols, 0.8.1 also gives us a new and beautiful client interface.

Command line interface

In my opinion, the most interesting feature in 0.8.1 is nmcli, A NetworkManager command line interface. Although NetworkManager has made a huge leap in managing network connections, the old-style management method ignores the command line interface. Is it wrong to configure the network with only the GUI?

There are several problems. Some users may not use the desktop environment or window manager that can easily support the NetworkManager applet. Some people may not use the GUI environment at all. Users may also want to write scripts to manage network interfaces. If the only available controller is GUI, this will become very difficult.

Finally, NetworkManager has its own CLI tool, nmcli. You can use nmcli to query the network connection status or manage the connection. This tool is still a bit primitive, but its syntax is relatively simple, and it is not difficult for those who really need to use NetworkManager In the CLI. For example, to list network interfaces in the system, you only need to run:

Nmcli dev list will display some output similar to the following:

 
 

  
  
- Device: eth0 -----------------------------------------------------------------  
  
  
Type 802-3-ethernet  
  
  
Driver pcnet32 
  
  
State connected  
  
  
Default no  
  
  
HW Address 00:0C:29:C3:87:30 
  
  
 
  
  
Capabilities:  
  
  
Carrier Detect yes  
  
  
 
  
  
Wired Properties  
  
  
Carrier on  
  
  
 
  
  
IPv4 Settings:  
  
  
Address 172.16.146.140 
  
  
Prefix 24 (255.255.255.0)  
  
  
Gateway 172.16.146.2 
  
  
 
  
  
DNS 172.16.146.2 
  
  
 
 
 

If you want to close a connection, you can use something like nmcli con down id <id>. Here <id> is the ID of a connection. Nmcli is not as flexible and functional as ifconfig, but it is just the beginning.

Future Prospects

Without a doubt, NetworkManager has not been completed yet, and may never be completed. There are always new devices to support and new features to be added. In addition, NetworkManager makes it easy for many users to use mainstream and standard network configurations, but does not necessarily adapt to uncommon configurations.

For example, it is very likely that functions in versions 0.8.2 or later include the network interface bonding and assigning a PPPoE address and a local address for an Ethernet interface at the same time.

In any case, NetworkManager has become a killer feature on Linux Desktop. If you have never thought about how complicated it is to manage your home, office, and various network connections on the road, you can thank NetworkManager for making your life easier.