Você pode usar nmcli
para realizar essa operação:
nmcli nm enable false
nmcli
páginas do homem :
enable [true|false]
Get networking-enabled status or enable/disable
networking by NetworkManager. All interfaces managed by
NetworkManager are deactivated when networking has been
disabled.
Reference to D-Bus:
interface: org.freedesktop.NetworkManager
method: Enable
arguments: TRUE or FALSE