path: root/man/NetworkManager.8

'\" t
.\"     Title: NetworkManager
.\"    Author: 
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\"      Date: 06/28/2023
.\"    Manual: Network management daemons
.\"    Source: NetworkManager 1.42.8
.\"  Language: English
.\"
.TH "NETWORKMANAGER" "8" "" "NetworkManager 1\&.42\&.8" "Network management daemons"
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.SH "NAME"
NetworkManager \- network management daemon
.SH "SYNOPSIS"
.HP \w'\fBNetworkManager\ \fR\fB[OPTIONS...]\fR\ 'u
\fBNetworkManager \fR\fB[OPTIONS...]\fR
.SH "DESCRIPTION"
.PP
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\&.
.SH "DISPATCHER SCRIPTS"
.PP
NetworkManager\-dispatcher service can execute scripts for the user in response to network events\&. See
\fBNetworkManager-dispatcher\fR(8)
manual\&.
.SH "OPTIONS"
.PP
The following options are understood:
.PP
\fB\-\-version\fR | \fB\-V\fR
.RS 4
Print the NetworkManager software version and exit\&.
.RE
.PP
\fB\-\-help\fR | \fB\-h\fR
.RS 4
Print NetworkManager\*(Aqs available options and exit\&.
.RE
.PP
\fB\-\-no\-daemon\fR | \fB\-n\fR
.RS 4
Do not daemonize\&.
.RE
.PP
\fB\-\-debug\fR | \fB\-d\fR
.RS 4
Do not daemonize, and direct log output to the controlling terminal in addition to syslog\&.
.RE
.PP
\fB\-\-pid\-file\fR | \fB\-p\fR
.RS 4
Specify location of a PID file\&. The PID file is used for storing PID of the running process and prevents running multiple instances\&.
.RE
.PP
\fB\-\-state\-file\fR
.RS 4
Specify file for storing state of the NetworkManager persistently\&. If not specified, the default value of
/var/lib/NetworkManager/NetworkManager\&.state
is used\&.
.RE
.PP
\fB\-\-config\fR
.RS 4
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 \*(Aqnm\-system\-settings\&.conf\*(Aq if located in the same directory\&. See
\fBNetworkManager.conf\fR(5)
for more information on configuration file\&.
.RE
.PP
\fB\-\-configure\-and\-quit\fR [initrd]
.RS 4
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\&.
.RE
.PP
\fB\-\-plugins\fR
.RS 4
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
\fBNetworkManager.conf\fR(5)
for supported options\&.
.RE
.PP
\fB\-\-log\-level\fR
.RS 4
Sets how much information NetworkManager sends to the log destination (usually syslog\*(Aqs "daemon" facility)\&. By default, only informational, warning, and error messages are logged\&. See the section on
logging
in
\fBNetworkManager.conf\fR(5)
for more information\&.
.RE
.PP
\fB\-\-log\-domains\fR
.RS 4
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
\fBNetworkManager.conf\fR(5)
for more information\&.
.RE
.PP
\fB\-\-print\-config\fR
.RS 4
Print the NetworkManager configuration to stdout and exit\&. See
\fBNetworkManager.conf\fR(5)\&. This does not include connection profiles\&. View them with
\fBnmcli connection\fR\&.
.sp
This reads configuration files from disk\&. If NetworkManager is currently running, make sure that it has the same configuration loaded\&.
.RE
.SH "UDEV PROPERTIES"
.PP
\fBudev\fR(7)
device manager is used for the network device discovery\&. The following property influences how NetworkManager manages the devices:
.PP
\fINM_UNMANAGED\fR
.RS 4
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
\fBnmcli device set "$DEVICE" managed yes\fR
or
"device*\&.managed=1"
in NetworkManager\&.conf\&.
.RE
.SH "SIGNALS"
.PP
NetworkManager process handles the following signals:
.PP
\fISIGHUP\fR
.RS 4
The signal causes a reload of NetworkManager\*(Aqs 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\*(Aqs reload action
.RE
.PP
\fISIGUSR1\fR
.RS 4
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\&.
.RE
.PP
\fISIGUSR2\fR
.RS 4
The signal has no effect at the moment but is reserved for future use\&.
.RE
.PP
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\&.
.SH "DEBUGGING"
.PP
NetworkManager only configures your system\&. So when your networking setup doesn\*(Aqt 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\&.
.PP
You can for example try to
\fBping\fR
hosts (by IP address or DNS name), look at
\fBip link show\fR,
\fBip address show\fR
and
\fBip route show\fR, and look at
/etc/resolv\&.conf
for name resolution issues\&. Also look at the connection profiles that you have configured in NetworkManager (\fBnmcli connection\fR
and
\fBnmcli connection show "$PROFILE"\fR) and the configured interfaces (\fBnmcli device\fR)\&.
.PP
If that does not suffice, look at the logfiles of NetworkManager\&. NetworkManager logs to syslog, so depending on your system configuration you can call
\fBjournalctl\fR
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
\fBnmcli general logging level TRACE domains ALL\fR\&. But usually a better way is to collect full logs from the start, by configuring
level=TRACE
in NetworkManager\&.conf\&. See
\fBNetworkManager.conf\fR(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
\fBjournald.conf\fR(5)
manual)\&.
.PP
NetworkManager does not log any secrets\&. However, you are advised to check whether anything private sensitive gets logged before posting\&. When reporting an issue, provide complete logs and avoid modifications (for privacy) that distort the meaning\&.
.SH "/VAR/LIB/NETWORKMANAGER/SECRET_KEY AND /ETC/MACHINE\-ID"
.PP
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\*(Aqs 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\&.
.PP
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
\fBmachine-id\fR(5))\&.
.PP
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\&.
.PP
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\&.
.SH "BUGS"
.PP
Please report any bugs you find in NetworkManager at the
\m[blue]\fBNetworkManager issue tracker\fR\m[]\&\s-2\u[1]\d\s+2\&.
.SH "SEE ALSO"
.PP
\m[blue]\fBNetworkManager home page\fR\m[]\&\s-2\u[2]\d\s+2,
\fBNetworkManager.conf\fR(5),
\fBNetworkManager-dispatcher\fR(8),
\fBNetworkManager-wait-online.service\fR(8),
\fBnmcli\fR(1),
\fBnmcli-examples\fR(7),
\fBnm-online\fR(1),
\fBnm-settings\fR(5),
\fBnm-applet\fR(1),
\fBnm-connection-editor\fR(1),
\fBudev\fR(7)
.SH "NOTES"
.IP " 1." 4
NetworkManager issue tracker
.RS 4
\%https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/issues
.RE
.IP " 2." 4
NetworkManager home page
.RS 4
\%https://networkmanager.dev
.RE