Linux Network Manager
NetworkManager
NetworkManage attempts to keep an active network connection available at all times.NetworkManager is composed of two layers:
- A daemon running as root: network-manager.
- A front-end: nmcli and nmtui (enclosed in package network-manager)
NetworkManager keeps connection information on known individual networks in configuration files called profiles, sometimes referred to as connections only.
Profiles are stored at /etc/NetworkManager/system-connections/.
The options used in the profile can be found in the manpage on nm-settings:
man nm-settings
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.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.
nmcli
The nmcli (NetworkManager Command Line Interface) command-line utility can be utilized as a replacement for nm-applet or other graphical clients.The basic format of a nmcli command is as follows:
nmcli [OPTIONS] OBJECT { COMMAND | help } [ARGUMENTS...]
where OBJECT can be one of the following options:
- general
- networking
- radio
- connection
- device
- agent
- monitor
COMMAND
General Commands
nmcli general { status | hostname | permissions | logging } [ARGUMENTS...]
- status Show overall status of NetworkManager.
- hostname [hostname] Get and change system hostname.
- permissions Show the permissions a caller has for various authenticated operations that NetworkManager provides, like enable and disable networking, changing Wi-Fi and WWAN state, modifying connections, etc.
- logging [level level] [domains domains...] Get and change NetworkManager logging level and domains.
This is the default action, when no additional command is provided for nmcli general.
With no arguments, this prints currently configured hostname.
When you pass a hostname, it will be handed over to NetworkManager to be set as a new system hostname. The hostname is stored in /etc/hostname file in most distributions.
Without any argument current logging level and domains are shown.
In order to change logging state, provide level and, or, domain parameters. See NetworkManager.conf(5) for available level and domain values.
Networking Control Commands
nmcli networking { on | off | connectivity } [ARGUMENTS...]
- on, off Enable or disable networking control by NetworkManager.
- connectivity [check] Get network connectivity state.
- none the host is not connected to any network.
- portal the host is behind a captive portal and cannot reach the full Internet.
- limited the host is connected to a network, but it has no access to the Internet.
- full the host is connected to a network and has full access to the Internet.
- unknown the connectivity status cannot be found out.
All interfaces managed by NetworkManager are deactivated when networking is disabled.
The optional check argument tells NetworkManager to re-check the connectivity, else the most recent known connectivity state is displayed without re-checking.
Possible states are:
Radio Transmission Control Commands
nmcli radio { all | wifi | wwan } [ARGUMENTS...]
Show radio switches status, or enable and disable the switches.
- wifi [ on | off ] Show or set status of Wi-Fi in NetworkManager.
- on enables Wi-Fi
- off disables Wi-Fi
- wwan [ on | off ] Show or set status of WWAN (mobile broadband) in NetworkManager.
- on enables mobile broadband
- off disables it
- all [ on | off ] Show or set all previously mentioned radio switches at the same time.
If no arguments are supplied, Wi-Fi status is printed;
If no arguments are supplied, mobile broadband status is printed;
Examples
- How to change MTU
$ nmcli connection show mymodem | grep mtu
gsm.mtu: auto
$ ifconfig mhi_mbim0
mhi_mbim0: flags=209<UP,POINTOPOINT,RUNNING,NOARP> mtu 1500
inet 10.108.8.23 netmask 255.255.255.240 destination 10.108.8.23
unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 txqueuelen 1000 (UNSPEC)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 40 bytes 3520 (3.5 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
$ sudo nmcli connection modify mymodem gsm.mtu 1430
$ nmcli connection show mymodem | grep mtu
gsm.mtu: 1430
$ sudo systemctl restart NetworkManager
$ nmcli connection show mymodem | grep mtu
gsm.mtu: 1430
$ ifconfig mhi_mbim0
mhi_mbim0: flags=209<UP,POINTOPOINT,RUNNING,NOARP> mtu 1430
inet 10.108.38.107 netmask 255.255.255.248 destination 10.108.38.107
unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 txqueuelen 1000 (UNSPEC)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 54 bytes 4752 (4.7 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
INTRODUCTION TO NETWORKMANAGER DEBUGGING
Setting the NetworkManager log level
/etc/NetworkManager/conf.d/95-nm-debug.conf:[logging] domains=ALL:DEBUGRestart:
$ sudo systemctl restart NetworkManagerCheck th elog:
$ sudo journalctl -u NetworkManager.service
NetworkManager Reference Manual
I. Manual Pages
NetworkManager — network management daemon
NetworkManager.conf — NetworkManager configuration file
nmcli — command-line tool for controlling NetworkManager
nmcli-examples — usage examples of nmcli
nmtui — Text User Interface for controlling NetworkManager
nm-settings-dbus — Description of settings and properties of NetworkManager connection profiles on the D-Bus API
nm-settings-nmcli — Description of settings and properties of NetworkManager connection profiles for nmcli
nm-settings-keyfile — Description of keyfile settings plugin
nm-settings-ifcfg-rh — Description of ifcfg-rh settings plugin
nm-online — ask NetworkManager whether the network is connected
nm-initrd-generator — early boot NetworkManager configuration generator
nm-cloud-setup — Overview of Automatic Network Configuration in Cloud
nm-openvswitch — overview of NetworkManager Open vSwitch support
II. Network Configuration Setting Specification
connection — General Connection Profile Settings
6lowpan — 6LoWPAN Settings
802-1x — IEEE 802.1x Authentication Settings
adsl — ADSL Settings
bluetooth — Bluetooth Settings
bond — Bonding Settings
bridge — Bridging Settings
bridge-port — Bridge Port Settings
cdma — CDMA-based Mobile Broadband Settings
dcb — Data Center Bridging Settings
dummy — Dummy Link Settings
ethtool — Ethtool Ethernet Settings
generic — Generic Link Settings
gsm — GSM-based Mobile Broadband Settings
infiniband — Infiniband Settings
ipv4 — IPv4 Settings
ipv6 — IPv6 Settings
ip-tunnel — IP Tunneling Settings
macsec — MACSec Settings
macvlan — MAC VLAN Settings
match — Match settings
802-11-olpc-mesh — OLPC Wireless Mesh Settings
ovs-bridge — OvsBridge Link Settings
ovs-dpdk — OvsDpdk Link Settings
ovs-interface — Open vSwitch Interface Settings
ovs-patch — OvsPatch Link Settings
ovs-port — OvsPort Link Settings
ppp — Point-to-Point Protocol Settings
pppoe — PPP-over-Ethernet Settings
proxy — WWW Proxy Settings
serial — Serial Link Settings
sriov — SR-IOV settings
tc — Linux Traffic Control Settings
team — Teaming Settings
team-port — Team Port Settings
tun — Tunnel Settings
user — General User Profile Settings
vlan — VLAN Settings
vpn — VPN Settings
vrf — VRF settings
vxlan — VXLAN Settings
wifi-p2p — Wi-Fi P2P Settings
wimax — WiMax Settings
802-3-ethernet — Wired Ethernet Settings
wireguard — WireGuard Settings
802-11-wireless — Wi-Fi Settings
Properties:- band 802.11 frequency band of the network.
- "a" for 5GHz 802.11a
- "bg" for 2.4GHz 802.11
This setting depends on specific driver capability and may not work with all drivers.
留言