Ubuntu Manpage: NetworkManager - network management daemon

Provided by: network-manager_1.2.6-0ubuntu0.16.04.3_amd64

NAME

       NetworkManager - network management daemon

SYNOPSIS

       NetworkManager [OPTIONS...]

DESCRIPTION

       The NetworkManager daemon attempts to make networking configuration and operation as
       painless and automatic as possible by managing the primary network connection and other
       network interfaces, like Ethernet, WiFi, and Mobile Broadband devices. NetworkManager will
       connect any network device when a connection for that device becomes available, unless
       that behavior is disabled. Information about networking is exported via a D-Bus interface
       to any interested application, providing a rich API with which to inspect and control
       network settings and operation.

DISPATCHER SCRIPTS

NetworkManager will execute scripts in the /etc/NetworkManager/dispatcher.d directory or
subdirectories in alphabetical order in response to network events. Each script should be
a regular executable file owned by root. Furthermore, it must not be writable by group or
other, and not setuid.

Each script receives two arguments, the first being the interface name of the device an
operation just happened on, and second the action. For device actions, the interface is
the name of the kernel interface suitable for IP configuration. Thus it is either
VPN_IP_IFACE, DEVICE_IP_IFACE, or DEVICE_IFACE, as applicable. For the hostname action it
is always "none".

The actions are:

pre-up
The interface is connected to the network but is not yet fully activated. Scripts
acting on this event must be placed or symlinked into the
/etc/NetworkManager/dispatcher.d/pre-up.d directory, and NetworkManager will wait for
script execution to complete before indicating to applications that the interface is
fully activated.

up
The interface has been activated.

pre-down
The interface will be deactivated but has not yet been disconnected from the network.
Scripts acting on this event must be placed or symlinked into the
/etc/NetworkManager/dispatcher.d/pre-down.d directory, and NetworkManager will wait
for script execution to complete before disconnecting the interface from its network.
Note that this event is not emitted for forced disconnections, like when carrier is
lost or a wireless signal fades. It is only emitted when there is an opportunity to
cleanly handle a network disconnection event.

down
The interface has been deactivated.

vpn-pre-up
The VPN is connected to the network but is not yet fully activated. Scripts acting on
this event must be placed or symlinked into the
/etc/NetworkManager/dispatcher.d/pre-up.d directory, and NetworkManager will wait for
script execution to complete before indicating to applications that the VPN is fully
activated.

vpn-up
A VPN connection has been activated.

vpn-pre-down
The VPN will be deactivated but has not yet been disconnected from the network.
Scripts acting on this event must be placed or symlinked into the
/etc/NetworkManager/dispatcher.d/pre-down.d directory, and NetworkManager will wait
for script execution to complete before disconnecting the VPN from its network. Note
that this event is not emitted for forced disconnections, like when the VPN terminates
unexpectedly or general connectivity is lost. It is only emitted when there is an
opportunity to cleanly handle a VPN disconnection event.

vpn-down
A VPN connection has been deactivated.

hostname
The system hostname has been updated. Use gethostname(2) to retrieve it. The interface
name (first argument) is empty and no environment variable is set for this action.

dhcp4-change
The DHCPv4 lease has changed (renewed, rebound, etc).

dhcp6-change
The DHCPv6 lease has changed (renewed, rebound, etc).

The environment contains more information about the interface and the connection. The
following variables are available for the use in the dispatcher scripts:

CONNECTION_UUID
The UUID of the connection profile.

CONNECTION_ID
The name (ID) of the connection profile.

CONNECTION_DBUS_PATH
The NetworkManager D-Bus path of the connection.

CONNECTION_FILENAME
The backing file name of the connection profile (if any).

CONNECTION_EXTERNAL
If "1", this indicates that the connection describes a network configuration created
outside of NetworkManager.

DEVICE_IFACE
The interface name of the control interface of the device. Depending on the device
type, this differs from DEVICE_IP_IFACE. For example for ADSL devices, this could be
'atm0' or for WWAN devices it might be 'ttyUSB0'.

DEVICE_IP_IFACE
The IP interface name of the device. This is the network interface on which IP
addresses and routes will be configured.

IP4_ADDRESS_N
The IPv4 address in the format "address/prefix gateway", where N is a number from 0 to
(# IPv4 addresses - 1). gateway item in this variable is deprecated, use IP4_GATEWAY
instead.

IP4_NUM_ADDRESSES
The variable contains the number of IPv4 addresses the script may expect.

IP4_GATEWAY
The gateway IPv4 address in traditional numbers-and-dots notation.

IP4_ROUTE_N
The IPv4 route in the format "address/prefix next-hop metric", where N is a number
from 0 to (# IPv4 routes - 1).

IP4_NUM_ROUTES
The variable contains the number of IPv4 routes the script may expect.

IP4_NAMESERVERS
The variable contains a space-separated list of the DNS servers.

IP4_DOMAINS
The variable contains a space-separated list of the search domains.

DHCP4_<dhcp-option-name>
If the connection used DHCP for address configuration, the received DHCP configuration
is passed in the environment using standard DHCP option names, prefixed with "DHCP4_",
like "DHCP4_HOST_NAME=foobar".

IP6_<name> and DHCP6_<name>
The same variables as for IPv4 are available for IPv6, but the prefixes are IP6_ and
DHCP6_ instead.

In case of VPN, VPN_IP_IFACE is set, and IP4_*, IP6_* variables with VPN prefix are
exported too, like VPN_IP4_ADDRESS_0, VPN_IP4_NUM_ADDRESSES.

Dispatcher scripts are run one at a time, but asynchronously from the main NetworkManager
process, and will be killed if they run for too long. If your script might take
arbitrarily long to complete, you should spawn a child process and have the parent return
immediately. Scripts that are symbolic links pointing inside the
/etc/NetworkManager/dispatcher.d/no-wait.d/ directory are run immediately, without waiting
for the termination of previous scripts, and in parallel. Also beware that once a script
is queued, it will always be run, even if a later event renders it obsolete. (Eg, if an
interface goes up, and then back down again quickly, it is possible that one or more "up"
scripts will be run after the interface has gone down.)

OPTIONS

The following options are understood:

--version | -V
Print the NetworkManager software version and exit.

--help | -h
Print NetworkManager's available options and exit.

--no-daemon | -n
Do not daemonize.

--debug | -d
Do not daemonize, and direct log output to the controlling terminal in addition to
syslog.

--pid-file | -p
Specify location of a PID file. The PID file is used for storing PID of the running
process and prevents running multiple instances.

--state-file
Specify file for storing state of the NetworkManager persistently. If not specified,
the default value of /var/lib/NetworkManager/NetworkManager.state is used.

--config
Specify configuration file to set up various settings for NetworkManager. If not
specified, the default value of /etc/NetworkManager/NetworkManager.conf is used with a
fallback to the older 'nm-system-settings.conf' if located in the same directory. See
NetworkManager.conf(5) for more information on configuration file.

--plugins
List plugins used to manage system-wide connection settings. This list has preference
over plugins specified in the configuration file. Currently supported plugins are:
keyfile, ifcfg-rh, ifcfg-suse, ifupdown.

--log-level
Sets how much information NetworkManager sends to the log destination (usually
syslog's "daemon" facility). By default, only informational, warning, and error
messages are logged. See the section on logging in NetworkManager.conf(5) for more
information.

--log-domains
A comma-separated list specifying which operations are logged to the log destination
(usually syslog). By default, most domains are logging-enabled. See the section on
logging in NetworkManager.conf(5) for more information.

--print-config
Print the NetworkManager configuration to stdout and exit.

UDEV PROPERTIES

       udev(7) device manager is used for the network device discovery. The following property
       influences how NetworkManager manages the devices:

       NM_UNMANAGED
           No default connection will be created and automatic activation will not be attempted
           when this property of a device is set to a true value ("1" or "true"). You will still
           be able to attach a connection to the device manually or observe externally added
           configuration such as addresses or routes.

           Create an udev rule that sets this property to prevent NetworkManager from interfering
           with virtual Ethernet device interfaces that are managed by virtualization tools.

SIGNALS

NetworkManager process handles the following signals:

SIGHUP
The signal causes a reload of NetworkManager's configuration. Note that not all
configuration parameters can be changed at runtime and therefore some changes may be
applied only after the next restart of the daemon. A SIGHUP also involves further
reloading actions, like doing a DNS update and restarting the DNS plugin. The latter
can be useful for example when using the dnsmasq plugin and changing its configuration
in /etc/NetworkManager/dnsmasq.d. However, it also means this will shortly interrupt
name resolution. In the future, there may be further actions added. A SIGHUP means to
update NetworkManager configuration and reload everything that is supported. Note that
this does not reload connections from disk. For that there is a D-Bus API and nmcli's
reload action

SIGUSR1
The signal forces a rewrite of DNS configuration. Contrary to SIGHUP, this does not
restart the DNS plugin and will not interrupt name resolution. In the future, further
actions may be added. A SIGUSR1 means to write out data like resolv.conf, or refresh a
cache. It is a subset of what is done for SIGHUP without reloading configuration from
disk.

SIGUSR2
The signal has no effect at the moment but is reserved for future use.

An alternative to a signal to reload configuration is the Reload D-Bus call. It allows for
more fine-grained selection of what to reload, it only returns after the reload is
complete, and it is guarded by PolicyKit.

DEBUGGING

       The following environment variables are supported to help debugging. When used in
       conjunction with the --no-daemon option (thus echoing PPP and DHCP helper output to
       stdout) these can quickly help pinpoint the source of connection issues. Also see the
       --log-level and --log-domains to enable debug logging inside NetworkManager itself.

       NM_PPP_DEBUG: When set to anything, causes NetworkManager to turn on PPP debugging in
       pppd, which logs all PPP and PPTP frames and client/server exchanges.