Although NetworkManager (nm) has been around for a while, not many people have used it on RasPiOS because dhcpcd was the default prior to Bookworm.
RasPiOS Bookworm now uses nm by default.
This page discusses nm sdm-fu and overall more depth on the network plugin.
On Bullseye and earlier systems, the network plugin by default uses dhcpcd for netman, as it is on an uncustomized RasPiOS. The network plugin accepts a file via the dhcpcdappend argument that is appended to /etc/dhcpcd.conf. The wpa argument file will be copied to /etc/wpa_supplicant/wpa_supplicant.conf. Alternatively, if the arguments wifissid, wifipassword, and wificountry are all set, wpa_supplicant.conf will be written with this configuration.
On Bookworm, nm is used by default for network management. You can also select nm on Bullseye with the netman=nm argument to the network plugin. Likewise, if you want to use dhcpcd on Bookworm, use netman=dhcpcd.
When configuring nm, a WiFi connection can be configured with the arguments wifissid, wifipassword, and wificountry. If all 3 are provided to the network plugin an nm connection file will be created using the wifissid as the connection name. If these arguments are not provided, the plugin will get the values from a provided wpa argument file. If neither of these are provided, no WiFi connection will be configured unless one is provided with an nmconn argument.
In addition to several arguments there are two nm-specific arguments: nmconf, and nmconn. Using these provides you with the best nm control in sdm.
As with other plugins, the best sdm-fu results from building static configuration files, and copying them into the IMG. With this approach the system can be fully configured from the first system boot.
nmconf files are nm configuration files. The nmconf argument can provide a comma-separated list of files on the host system. nm expects these files to be named something.conf
Similarly, nmconn files are nm connection keyfiles. These are also text-based. Network manager expects these to be named something.nmconnection. Each WiFi network requires a .nmconnection file.
One way to generate a .nmconnection is to use nmcli. This technique requires use of the nmcli --offline switch, which is supported only in Bookworm and later. This example on Bookworm is one long command line. See a note about WiFi autoconnect here.
nmcli --offline c add type wifi con-name your-name ifname wlan0 ssid your-ssid | \
nmcli --offline c modify wifi-sec.key-mgmt wpa-psk wifi-sec.psk your-password autoconnect false > your-connfile.nmconnectionThe above command would create your-connfile.nmconnection:
[connection]
id=your-name
uuid=d45eba01-916c-4b77-8f0e-01071f955727
type=wifi
autoconnect=false
interface-name=wlan0
[wifi]
mode=infrastructure
ssid=your-ssid
[wifi-security]
key-mgmt=wpa-psk
psk=your-password
[ipv4]
method=auto
[ipv6]
addr-gen-mode=default
method=auto
[proxy]
In order to generate a .nmconnection file using Bullseye or earlier, you must use nm running on a booted system. Once that system is configured with nm and available you can:
nmcli c add type wifi con-name your-name ifname wlan0 ssid your-ssid
nmcli c modify your-name wifi-sec.key-mgmt wpa-psk wifi-sec.psk your-password
Disable IPV6 on a WiFi connection
nmcli c modify your-name ipv6.method disabled
Disable IPV6 on the default eth0 connection
nmcli c modify Wired\ connection\ 1 ipv6.method disabled
Although nm uses wpa_supplicant, it does not specifically use the wpa_supplicant.conf file except as described above (by the network plugin).
Instead, nm communicates WiFi configuration information to wpa_supplicant over dbus. This enables a key feature of nm, the ability to easily switch WiFi connections.
By default, a new WiFi connection is created with autoconnect true. Perfect if you only have one WiFi connection. But, when you add a second one, which one is the one to connect by default?
For secondary, non-autoconnect connections, specify autconnect false so that they are actually not autoconnected.
man nm-settings-keyfile— Connection keyfileman nm-settings— More Connection settings (Advanced)man NetworkManager.conf— Overview of Network Manager configuration (Advanced)- Complete NetworkManager documentation