Which commands are required to restart a network interface in NetworkManager?

The commands that effectively restart a network interface in NetworkManager are to bring the connection down and then bring it back up using the nmcli tool. This is considered the correct method because nmcli (NetworkManager Command Line Interface) is specifically designed to manage NetworkManager's functionalities, including the control of network connections.

When the command nmcli con down connectionname is executed, it deactivates the specified connection, effectively bringing the network interface down. Following this, the nmcli con up connectionname command reactivates the connection, thus bringing the network interface back up. This two-step approach is essential in properly handling network interfaces managed by NetworkManager.

Other options presented do not align with how NetworkManager operates. The systemctl command suggests managing a service rather than a connection directly, which is not appropriate for restarting network interfaces under NetworkManager. The ifdown and ifup commands are older and more suited to classic network management (like ifupdown) outside the NetworkManager architecture. Lastly, using ip link set is a lower-level command that may not restart the network connection in the context of NetworkManager, as this command manages network interfaces at a lower level without considering NetworkManager's management of connections. Thus, the command