When I'm home, I use fiber-optic line with a dedicated old small router (YAMAHA RT107e) for access to the Internet. But I recently became anxious about the router. If it fails, how can I survive until I get another one? So, I tried to connect my Debian desktop PC to the fiber-optic line without the router. The PC have to talk to the other side of the line with PPPoE but I did not know how. In my PC, the Network Manager manages network configuration. So, I had to configure the Network Manager to utilize the pppoe like : nmcli connection add ifname eth0 connection.type pppoe username USERNAME password PASSWORD