輸入下方指令
sudo systemctl edit systemctl-networkd-wait-online.service
# 再ExecStart=/usr/lib/systemd/systemd-networkd-wait-online 加入--timeout=15
sudo systemctl daemon-reload
參考資料：
https://www.reddit.com/r/Ubuntu/comments/16xi5h0/how_do_i_fix_systemdnetworkdwaitonlineservice/