RHEL7: How to get started with NetworkManager.

Presentation

nmcli stands for Network Manager Command Line Interface.

With the Network Manager Text User Interface command called nmtui, it is part of the NetworkManager component in charge of the network subsystem (the NetworkManager changelog is available here).

nmcli is a new way to integrate network configuration into scripts.

Five domains are available:

• general: it deals with NetworkManager’s general status and operations,
• networking: it’s about overall networking control,
• radio: it manages NetworkManager radio switches,
• connection: it’s all about NetworkManager’s connections,
• device: it deals with devices managed by NetworkManager.

In addition, the display can be altered by some options: -p to get a nice output, -t to get a minimal one.
Shortcuts are intensively used: g for general, n for networking, etc.
It’s time to see what we can expect from this command.

General

To get a general status, type:

# nmcli general
STATE CONNECTIVITY WIFI-HW WIFI WWAN-HW WWAN
connected full enabled enabled enabled disabled

To get the same result in a better output, type:

# nmcli -p g
==============================================================
NetworkManager status
==============================================================
STATE CONNECTIVITY WIFI-HW WIFI WWAN-HW WWAN
--------------------------------------------------------------
connected full enabled enabled enabled disabled

To get some informations about the permissions, type:

# nmcli g permissions
PERMISSION VALUE
org.freedesktop.NetworkManager.enable-disable-network yes
org.freedesktop.NetworkManager.enable-disable-wifi yes
org.freedesktop.NetworkManager.enable-disable-wwan yes
org.freedesktop.NetworkManager.enable-disable-wimax yes
org.freedesktop.NetworkManager.sleep-wake yes
org.freedesktop.NetworkManager.network-control yes
org.freedesktop.NetworkManager.wifi.share.protected yes
org.freedesktop.NetworkManager.wifi.share.open yes
org.freedesktop.NetworkManager.settings.modify.system yes
org.freedesktop.NetworkManager.settings.modify.own yes
org.freedesktop.NetworkManager.settings.modify.hostname yes

To get some informations about the level of logging, type:

# nmcli g logging
LEVEL DOMAINS

WARN PLATFORM,RFKILL,ETHER,WIFI,BT,MB,DHCP4,DHCP6,PPP,IP4,IP6,AUTOIP4,DNS,VPN, SHARING,SUPPLICANT,AGENTS,SETTINGS,SUSPEND,CORE,DEVICE,OLPC,WIMAX,INFINIBAND,FIR EWALL,ADSL,BOND,VLAN,BRIDGE,TEAM,CONCHECK,DCB

To get the server hostname, type:

# nmcli g hostname
server.example.com

To assign a new hostname (here desktop.example.com) to the server, type:

# nmcli g hostname desktop.example.com

Networking

To know if you are connected, type:

# nmcli networking
enabled

Note: you can stop all connectivity by typing: # nmcli n off

To know the kind of connectivity you’ve got, type:

# nmcli n connectivity
full

Note: the other values can be: none if you don’t get any connectivity, portal if you are behind a captive portal and can’t reach the full Internet, limited if you are connected to a host but without access to the Internet, unknown if your status can’t be defined.

Radio

To get the general status of radio, type:

# nmcli radio
WIFI-HW WIFI WWAN-HW WWAN
enabled enabled enabled disabled

To get the status of wifi, type:

# nmcli radio wifi
enabled

Note: Wifi can be enabled or disabled by adding respectively on and off to the previous command.

To get the status of mobile broadband, type:

# nmcli radio wwan
disabled

Connection

To get the list of all the available network configurations, type:

# nmcli connection
NAME UUID TYPE TIMESTAMP-REAL
eth0 94aaedf1-ca71-4789-87c8-88e5367125d5 802-3-ethernet Tue 28 Jan 2014 02:40:18 AM CET
eth0 914d2052-f0fd-4a05-86b7-405512427101 802-3-ethernet never
EEE 9a3642f0-600d-43f9-b9ce-7e555dd7b45d 802-11-wireless Tue 28 Jan 2014 01:01:58 PM CET

To display details about the network configuration that has never been used, type:

# nmcli c show configured 914d2052-f0fd-4a05-86b7-405512427101
connection.id: eth0
connection.uuid: 914d2052-f0fd-4a05-86b7-405512427101
connection.interface-name: eth0
connection.type: 802-3-ethernet
connection.autoconnect: yes
connection.timestamp: 0
connection.read-only: no
connection.permissions:
connection.zone: --
connection.master: --
connection.slave-type: --
connection.secondaries:
connection.gateway-ping-timeout: 0
802-3-ethernet.port: --
802-3-ethernet.speed: 0
802-3-ethernet.duplex: --
802-3-ethernet.auto-negotiate: yes
802-3-ethernet.mac-address: 52:54:00:8A:45:52
802-3-ethernet.cloned-mac-address: --
802-3-ethernet.mac-address-blacklist:
802-3-ethernet.mtu: auto
802-3-ethernet.s390-subchannels:
802-3-ethernet.s390-nettype: --
802-3-ethernet.s390-options:
ipv4.method: manual
ipv4.dns: 192.168.1.1
ipv4.dns-search:
ipv4.addresses: { ip = 192.168.1.2/24, gw = 192.168.1.1 }
ipv4.routes:
ipv4.ignore-auto-routes: no
ipv4.ignore-auto-dns: no
ipv4.dhcp-client-id: --
ipv4.dhcp-send-hostname: yes
ipv4.dhcp-hostname: --
ipv4.never-default: no
ipv4.may-fail: yes
ipv6.method: ignore
ipv6.dns:
ipv6.dns-search:
ipv6.addresses:
ipv6.routes:
ipv6.ignore-auto-routes: no
ipv6.ignore-auto-dns: no
ipv6.never-default: no
ipv6.may-fail: yes
ipv6.ip6-privacy: -1 (unknown)
ipv6.dhcp-hostname: --

To delete this network configuration, type:

# nmcli c delete 914d2052-f0fd-4a05-86b7-405512427101

To get the list of the active network configurations, type:

# nmcli c show active
NAME UUID DEVICES DEFAULT VPN MASTER-PATH
eth0 94aaedf1-ca71-4789-87c8-88e5367125d5 eth0 no no --

Note: It would have been possible to activate the previous network configuration before removal by typing:

# nmcli c up 914d2052-f0fd-4a05-86b7-405512427101

To get more information about connection management, go to the page about configuring IPv4 addresses.

You can also edit any kind of connection in an interactive way:

# nmcli c edit 914d2052-f0fd-4a05-86b7-405512427101

===| nmcli interactive connection editor |===

Editing existing '802-3-ethernet' connection: '914d2052-f0fd-4a05-86b7-405512427101'

Type 'help' or '?' for available commands.
Type 'describe [<setting>.<prop>]' for detailed property description.

You may edit the following settings: connection, 802-3-ethernet (ethernet), 802-1x, ipv4, ipv6, dcb
nmcli>

Device

To get the list of all the devices, type:

# nmcli device
DEVICE TYPE STATE
eth0 ethernet connected
wlp3s0 wifi disconnected
lo loopback unmanaged

To get details about all the devices, type:

# nmcli d show
GENERAL.DEVICE: eth0
GENERAL.TYPE: ethernet
GENERAL.VENDOR: Red Hat, Inc
GENERAL.PRODUCT: Virtio network device
GENERAL.DRIVER: virtio_net
GENERAL.DRIVER-VERSION: 1.0.0
GENERAL.FIRMWARE-VERSION:
GENERAL.HWADDR: 52:54:00:8A:45:52
GENERAL.STATE: 100 (connected)
GENERAL.REASON: 0 (No reason given)
GENERAL.UDI: /sys/devices/pci0000:00/0000:00:03.0/virtio0/net/eth0
GENERAL.IP-IFACE: eth0
GENERAL.NM-MANAGED: yes
GENERAL.AUTOCONNECT: yes
GENERAL.FIRMWARE-MISSING: no
GENERAL.CONNECTION: /org/freedesktop/NetworkManager/ActiveConnection/0
CAPABILITIES.CARRIER-DETECT: yes
CAPABILITIES.SPEED: unknown
CONNECTIONS.AVAILABLE-CONNECTION-PATHS: /org/freedesktop/NetworkManager/Settings/{1}
CONNECTIONS.AVAILABLE-CONNECTIONS[1]: 94aaedf1-ca71-4789-87c8-88e5367125d5 | eth0
WIRED-PROPERTIES.CARRIER: on
IP4.ADDRESS[1]: ip = 192.168.1.2/24, gw = 0.0.0.0
IP4.ROUTE[1]: dst = 169.254.0.0/16, nh = 0.0.0.0, mt = 1002
IP6.ADDRESS[1]: ip = fe80::5054:ff:fe8a:4552/64, gw = ::

GENERAL.DEVICE: wlp3s0
GENERAL.TYPE: wifi
GENERAL.VENDOR: Realtek Semiconductor Co., Ltd.
GENERAL.PRODUCT: RTL8191SEvB Wireless LAN Controller
GENERAL.DRIVER: rtl8192se
GENERAL.DRIVER-VERSION: 3.10.0-54.0.1.el7.x86_64
GENERAL.FIRMWARE-VERSION: N/A
GENERAL.HWADDR: B4:82:FE:90:41:45
GENERAL.STATE: 30 (disconnected)
GENERAL.REASON: 42 (The supplicant is now available)
GENERAL.UDI: /sys/devices/pci0000:00/0000:00:1c.1/0000:03:00.0/net/wlp3s0
GENERAL.IP-IFACE:
GENERAL.NM-MANAGED: yes
GENERAL.AUTOCONNECT: yes
GENERAL.FIRMWARE-MISSING: no
GENERAL.CONNECTION: not connected
CAPABILITIES.CARRIER-DETECT: no
CAPABILITIES.SPEED: unknown
CONNECTIONS.AVAILABLE-CONNECTION-PATHS:
WIFI-PROPERTIES.WEP: yes
WIFI-PROPERTIES.WPA: yes
WIFI-PROPERTIES.WPA2: yes
WIFI-PROPERTIES.TKIP: yes
WIFI-PROPERTIES.CCMP: yes
WIFI-PROPERTIES.AP: yes
WIFI-PROPERTIES.ADHOC: yes
AP[1].*:
AP[1].SSID: AAA
AP[1].MODE: Infra
AP[1].CHAN: 1
AP[1].RATE: 54 MB/s
AP[1].SIGNAL: 10
AP[1].BARS: ▂___
AP[1].SECURITY: WPA1
AP[2].*:
AP[2].SSID: BBB
AP[2].MODE: Infra
AP[2].CHAN: 11
AP[2].RATE: 54 MB/s
AP[2].SIGNAL: 100
AP[2].BARS: ▂▄▆█
AP[2].SECURITY: WPA1
AP[3].*:
AP[3].SSID: CCC
AP[3].MODE: Infra
AP[3].CHAN: 11
AP[3].RATE: 54 MB/s
AP[3].SIGNAL: 100
AP[3].BARS: ▂▄▆█
AP[3].SECURITY: WPA2 802.1X
AP[4].*:
AP[4].SSID: DDD
AP[4].MODE: Infra
AP[4].CHAN: 6
AP[4].RATE: 54 MB/s
AP[4].SIGNAL: 100
AP[4].BARS: ▂▄▆█
AP[4].SECURITY: WPA1 WPA2
AP[5].*:
AP[5].SSID: EEE
AP[5].MODE: Infra
AP[5].CHAN: 11
AP[5].RATE: 54 MB/s
AP[5].SIGNAL: 100
AP[5].BARS: ▂▄▆█
AP[5].SECURITY: WEP

GENERAL.DEVICE: lo
GENERAL.TYPE: loopback
GENERAL.VENDOR: --
GENERAL.PRODUCT: --
GENERAL.DRIVER: unknown
GENERAL.DRIVER-VERSION:
GENERAL.FIRMWARE-VERSION:
GENERAL.HWADDR: (unknown)
GENERAL.STATE: 10 (unmanaged)
GENERAL.REASON: 0 (No reason given)
GENERAL.UDI: /sys/devices/virtual/net/lo
GENERAL.IP-IFACE: lo
GENERAL.NM-MANAGED: no
GENERAL.AUTOCONNECT: yes
GENERAL.FIRMWARE-MISSING: no
GENERAL.CONNECTION: not connected
CAPABILITIES.CARRIER-DETECT: yes
CAPABILITIES.SPEED: unknown
CONNECTIONS.AVAILABLE-CONNECTION-PATHS:
IP4.ADDRESS[1]: ip = 127.0.0.1/8, gw = 0.0.0.0
IP6.ADDRESS[1]: ip = ::1/128, gw = ::

To get the list of available wifi access points, type:

# nmcli d wifi
* SSID MODE CHAN RATE SIGNAL BARS SECURITY
AAA Infra 11 54 MB/s 55 ▂▄__ WPA2 802.1X
BBB Infra 11 54 MB/s 54 ▂▄__ WPA1
CCC Infra 1 54 MB/s 49 ▂▄__ WPA1
DDD Infra 11 54 MB/s 44 ▂▄__ WPA1 802.1X
EEE Infra 11 54 MB/s 92 ▂▄▆█ WEP

To connect to a wifi access point specified by a SSID (here EEE), type:

# nmcli d wifi connect EEE password '12345678901234567890123456'

To request that NetworkManager rescans for available access points, type:

# nmcli d wifi rescan

Sources: nmcli and nmcli-examples man pages.

Additional Resources

You can browse the official NetworkManager documentation (easier than man pages).
Lubomir Rintel’s blog, Thomas Haller’s blog, and Dan Williams’ blog provide information about NetworkManager and were used for this article about some NetworkManager evolutions.
Francisco Giudici gave a presentation about NetworkManager at DevConf CZ (24min/2018).
Daniel Aleksandersen explains How to take back control of /etc/resolv.conf on Linux.