-THEORY OF OPERATION:
-NetworkManager attempts to keep an active network connection available at all times. It is intended only for the desktop use-case, and is not intended for usage on servers. At this time, it does not support static IP addresses on network interfaces, and requires DHCP to be used instead. The point of NetworkManager is to make networking configuration and setup as painless and automatic as possible. If using DHCP, NetworkManager is _intended_ to replace default routes, obtain IP addresses from a DHCP server, and change nameservers whenever it sees fit. If you have special needs, we'd like to hear about them, but understand that NetworkManager is not intended to serve the needs of all users.
+******************
+2008-12-11: NetworkManager core daemon has moved to git.freedesktop.org!
-
-From a list of all adapters currently installed on the system, NetworkManager will first try a wired and then a wireless adapter. Wireless adapters that support wireless scanning are preferred over ones that cannot. NetworkManager does not try to keep a connection up as long as possible, meaning that plugging into a wired network will switch the connection to the wired network away from the wireless one.
+git clone git://git.freedesktop.org/git/NetworkManager/NetworkManager.git
+******************
-For wireless networking support, NetworkManager keeps two lists of wireless networks: a Trusted list, and a Preferred list. The Trusted list contains networks the user specifically adds to it, while the preferred list contains networks the user forces NetworkManager to connect to. For example, while the company's wireless network and WEP/WPA key would be preloaded into the Trusted Networks list, if the user wished to use the wireless network in a Starbucks, the user would explicitly tell NetworkManager to associate with that network. NetworkManager does not try to use _any_ available network in the area (a possible security risk), but will associate with any Trusted Network first, and Preferred Networks later. Preferred Networks are ones the user has explicitly made NetworkManager associate with at some previous time. So if the user walks into a Starbucks and explicitly asks NetworkManager to associate with that Starbucks network, NetworkManager will remember the Starbucks network information from that point on. Upon returning to that Starbucks, NetworkManager will attempt to associate _automatically_ with the Starbucks network since it is now in the Preferred Networks list. The point of this is to ensure that only the user can determine which wireless networks to associate with, and that the user is aware which networks are security risks and which are not.
-STRUCTURE:
+Networking that Just Works
+--------------------------
-NetworkManager runs as a root-user system level daemon, since it must manipulate hardware directly. It communicates over DBUS with at least one other daemon, the info-daemon. Since Trusted and Preferred Networks are user-specific, there must be some mechanism of getting this information per-user. NetworkManager cannot store that information as it is user-specific, and therefore communicates over DBUS to the info-daemon which provides those lists. NetworkManager also provides an API over DBUS for any DBUS-aware application to determine the current state of the network, including available wireless networks the computer is aware of and specific details about those networks. This API also provides the means for forcing NetworkManager to associate with a specific wireless network. Use of DBUS allows separation of NetworkManager, which requires no user-interface, and the parts of the user interface which might be desktop environment specific.
+NetworkManager attempts to keep an active network connection available at all
+times. The point of NetworkManager is to make networking configuration and
+setup as painless and automatic as possible. NetworkManager is intended to
+replace default route, replace other routes, set IP addresses, and in general
+configure networking as NM sees fit (with the possibility of manual override as
+necessary). In effect, the goal of NetworkManager is to make networking Just
+Work with a minimum of user hassle, but still allow customization and a high
+level of manual network control. If you have special needs, we'd like to hear
+about them, but understand that NetworkManager is not intended for every
+use-case.
-The info-daemon provides a DBUS service called NetworkManagerInfo, which should provide to NetworkManager the Trusted and Preferred Networks lists upon request. It also should be able to display a dialog to retrieve a WEP/WPA key or passphrase from the user when NetworkManager requests it. The GNOME version of NetworkManagerInfo, for example, stores Trusted and Preferred Networks in GConf, and proxies that information to NetworkManager upon request.
+NetworkManager will attempt to keep every network device in the system up and
+active, as long as the device is available for use (has a cable plugged in,
+the killswitch isn't turned on, etc). Network connections can be set to
+'autoconnect', meaning that NetworkManager will make that connection active
+whenever it and the hardware is available.
-Other UI bits might include a user-visible application (for example, the included GNOME Panel applet) providing a list of available wireless networks to the user and a means to manually select one to associate with.
+"Settings services" store lists of user- or administrator-defined "connections",
+which contain all the settings and parameters required to connect to a specific
+network. NetworkManager will _never_ activate a connection that is not in this
+list, or that the user has not directed NetworkManager to connect to.
+
+
+How it works:
+
+The NetworkManager daemon runs as a privileged service (since it must access
+and control hardware), but provides a D-Bus interface on the system bus to
+allow for fine-grained control of networking. NetworkManager does not store
+connections or settings, it is only the mechanism by which those connections
+are selected and activated.
+
+To store pre-defined network connections, two separate services, the "system
+settings service" and the "user settings service" store connection information
+and provide these to NetworkManager, also via D-Bus. Each settings service
+can determine how and where it persistently stores the connection information;
+for example, the GNOME applet stores its configuration in GConf, and the system
+settings service stores it's config in distro-specific formats, or in a distro-
+agnostic format, depending on user/administrator preference.
+
+A variety of other system services are used by NetworkManager to provide
+network functionality: wpa_supplicant for wireless connections and 802.1x
+wired connections, pppd for PPP and mobile broadband connections, DHCP clients
+for dynamic IP addressing, dnsmasq for proxy nameserver and DHCP server
+functionality for internet connection sharing, and avahi-autoipd for IPv4
+link-local addresses. Most communication with these daemons occurs, again,
+via D-Bus.
+
+
+Why doesn't my network Just Work?
+
+Driver problems are the #1 cause of why NetworkManager sometimes fails to
+connect to wireless networks. Often, the driver simply doesn't behave in a
+consistent manner, or is just plain buggy. NetworkManager supports _only_
+those drivers that are shipped with the upstream Linux kernel, because only
+those drivers can be easily fixed and debugged. ndiswrapper, vendor binary
+drivers, or other out-of-tree drivers may or may not work well with
+NetworkManager, precisely because they have not been vetted and improved by the
+open-source community, and because problems in these drivers usually cannot
+be fixed.
+
+Sometimes, command-line tools like 'iwconfig' will work, but NetworkManager will
+fail. This is again often due to buggy drivers, because these drivers simply
+aren't expecting the dynamic requests that NetworkManager and wpa_supplicant
+make. Driver bugs should be filed in the bug tracker of the distribution being
+run, since often distributions customize their kernel and drivers.
+
+Sometimes, it really is NetworkManager's fault. If you think that's the case,
+please file a bug at http://bugzilla.gnome.org and choose the NetworkManager
+component. Attaching the output of /var/log/messages or /var/log/daemon.log
+(wherever your distribution directs syslog's 'daemon' facility output) is often
+very helpful, and (if you can get) a working wpa_supplicant config file helps
+enormously.
projects / NetworkManager.git / blobdiff