Provided by: network-manager_1.36.6-0ubuntu2_amd64 bug


       NetworkManager - network management daemon


       NetworkManager [OPTIONS...]


       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, Wi-Fi, 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.


       NetworkManager-dispatcher service can execute scripts for the user in response to network
       events. See NetworkManager-dispatcher(8) manual.


       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

       --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.

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

           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.

       --configure-and-quit [initrd]
           Quit after all devices reach a stable state. The optional initrd parameter enables
           mode, where no processes are left running after NetworkManager stops, which is useful
           for running from an initial ramdisk on rearly boot.

           List plugins used to manage system-wide connection settings. This list has preference
           over plugins specified in the configuration file. See main.plugins setting in
           NetworkManager.conf(5) for supported options.

           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

           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 the NetworkManager configuration to stdout and exit.


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

           If set to "1" or "true", the device is configured as unmanaged by NetworkManager. Note
           that the user still can explicitly overrule this configuration via means like nmcli
           device set "$DEVICE" managed yes or "device*.managed=1" in NetworkManager.conf.


       NetworkManager process handles the following signals:

           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

           The signal forces a rewrite of DNS configuration. Contrary to SIGHUP, this does not
           restart the DNS plugin and will not interrupt name resolution. When NetworkManager is
           not managing DNS, the signal forces a restart of operations that depend on the DNS
           configuration (like the resolution of the system hostname via reverse DNS, or the
           resolution of WireGuard peers); therefore, it can be used to tell NetworkManager that
           the content of resolv.conf was changed externally. 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.

           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.


       NetworkManager only configures your system. So when your networking setup doesn't work as
       expected, the first step is to look at your system to understand what is actually
       configured, and whether that is correct. The second step is to find out how to tell
       NetworkManager to do the right thing.

       You can for example try to ping hosts (by IP address or DNS name), look at ip link show,
       ip address show and ip route show, and look at /etc/resolv.conf for name resolution
       issues. Also look at the connection profiles that you have configured in NetworkManager
       (nmcli connection and nmcli connection show "$PROFILE") and the configured interfaces
       (nmcli device).

       If that does not suffice, look at the logfiles of NetworkManager. NetworkManager logs to
       syslog, so depending on your system configuration you can call journalctl to get the logs.
       By default, NetworkManager logs are not verbose and thus not very helpful for
       investigating a problem in detail. You can change the logging level at runtime with nmcli
       general logging level TRACE domains ALL. But usually a better way is to collect full logs
       from the start, by configuring level=TRACE in NetworkManager.conf. See
       NetworkManager.conf(5) manual. Note that trace logs of NetworkManager are verbose and
       systemd-journald might rate limit some lines. Possibly disable rate limiting first with
       the RateLimitIntervalSec and RateLimitBurst options of journald (see journald.conf(5)


       The identity of a machine is important as various settings depend on it. For example,
       ipv6.addr-gen-mode=stable and ethernet.cloned-mac-address=stable generate identifiers by
       hashing the machine's identity. See also the connection.stable-id connection property
       which is a per-profile seed that gets hashed with the machine identity for generating such
       addresses and identifiers.

       If you backup and restore a machine, the identity of the machine probably should be
       preserved. In that case, preserve the files /var/lib/NetworkManager/secret_key and
       /etc/machine-id. On the other hand, if you clone a virtual machine, you probably want that
       the clone has a different identity. There is already existing tooling on Linux for
       handling /etc/machine-id (see machine-id(5)).

       The identity of the machine is determined by the /var/lib/NetworkManager/secret_key. If
       such a file does not exist, NetworkManager will create a file with random content. To
       generate a new identity just delete the file and after restart a new file will be created.
       The file should be read-only to root and contain at least 16 bytes that will be used to
       seed the various places where a stable identifier is used.

       Since 1.16.0, NetworkManager supports a version 2 of secret-keys. For such keys
       /var/lib/NetworkManager/secret_key starts with ASCII "nm-v2:" followed by at least 32
       bytes of random data. Also, recent versions of NetworkManager always create such kinds of
       secret-keys, when the file does not yet exist. With version 2 of the secret-key,
       /etc/machine-id is also hashed as part of the generation for addresses and identifiers.
       The advantage is that you can keep /var/lib/NetworkManager/secret_key stable, and only
       regenerate /etc/machine-id when cloning a VM.


       Please report any bugs you find in NetworkManager at the NetworkManager issue tracker[1].


       NetworkManager home page[2], NetworkManager.conf(5), NetworkManager-dispatcher(8),
       nmcli(1), nmcli-examples(7), nm-online(1), nm-settings(5), nm-applet(1), nm-connection-
       editor(1), udev(7)


        1. NetworkManager issue tracker

        2. NetworkManager home page