The Connectivity Refresh Vector
On an Ubuntu Linux desktop or server, the NetworkManager daemon is responsible for handling all dynamic network configurations, including Wi-Fi connections, VPN tunnels, and wired Ethernet profiles. Occasionally, following a system update, a router failure, or an interrupted VPN session, the networking stack can hang, leaving the machine completely disconnected from the internet. Rather than executing a highly disruptive full system reboot, administrators must know how to precisely restart the networking service.
How to Restart the Network Manager
You can force the system to aggressively cycle the network daemon, flushing stalled connections and requesting new IP leases, directly from the terminal.
1. Open your terminal application.
2. To cleanly restart the service using the modern systemd architecture, execute the following command with elevated privileges:
sudo systemctl restart NetworkManager
3. If your terminal returns directly to a blank prompt without displaying any text, the command was successful. You will likely lose SSH connectivity for a fraction of a second as the interfaces cycle.
4. To verify that the daemon has successfully reinitialized and is actively running, execute the status command:
sudo systemctl status NetworkManager
The output should display active (running) in green text, confirming that the networking stack has been completely reset and is ready to establish new connections.