NetworkManager

NetworkManager(8) is a high level network administration tool.

Installation

Most Linux distributions offer a networkmanager package.

Usage

nmcli(1) and nmtui(1) are bundled with NetworkManager(8).

NetworkManager(8) stores profiles of connections. These are then written to files in /etc/NetworkManager/system-connections/.

To list all connections, try:

nmcli connection show

To set a connection up or down, try:

nmcli connection up CONNECTION_UUID
nmcli connection down CONNECTION_UUID

To delete a connection (and erase the locally stored profile), try:

nmcli connection delete CONNECTION_UUID
# or
rm /etc/NetworkManager/system-connections/CONNECTION_UUID

WiFi

To list available Wi-Fi networks, try:

nmcli device wifi list

To connect to a new Wi-Fi network, thereby creating a connection, try:

nmcli device wifi connect NETWORK_SSID password NETWORK_PASSWORD

To turn off Wi-Fi entirely, try:

nmcli radio wifi off

Network Interfaces

To disconnect a network interface (like eth0), try:

nmcli device disconnect ifname IFNAME

Configurations

DHCP

NetworkManager(8) uses an internal DHCP client. To use a different client, edit /etc/NetworkManager/conf.d/dhcp-client.conf like:

[main]
dhcp=dhclient

Only dhclient(8) and dhcpcd(8) are allowed alternatives.

NetworkManager(8) broadcasts a machine's hostname. To disable this on a per-connection basis, edit /etc/NetworkManager/system-connections/CONNECTION_UUID like:

[ipv4]
dhcp-send-hostname=false

[ipv6]
dhcp-send-hostname=false

DNS

NetworkManager(8) tries to take ownership of DNS through the resolver file, /etc/resolv.conf. If another service tries to do the same, DNS can end up mangled.

To use a different client, edit /etc/NetworkManager/conf.d/dns.conf like:

[main]
dns=dnsmasq

Only dnsmasq(8) and systemd-resolved(8) are allowed alternatives.

As a workaround for compatibility with openresolv, edit /etc/NetworkManager/conf.d/rc-manager.conf like:

[main]
rc-manager=resolvconf

It is also possible to disable DNS operations entirely by setting dns=none.

Wi-Fi Backend

To use iwd(8) as the Wi-Fi backend, edit /etc/NetworkManager/conf.d/wifi_backend.conf like:

[device]
wifi.backend=iwd

See also

NetworkManager(8)

nmcli(1)

CategoryRicottone