KNXD.Socket

 [smarthome@SmartHomeNG ~]$ systemctl status knxd.socket
● knxd.socket - KNX Daemon (socket)
   Loaded: loaded (/lib/systemd/system/knxd.socket; enabled; vendor preset: enabled)
   Active: active (running) since Wed 2018-02-28 17:31:28 CET; 16min ago
   Listen: /var/run/knx (Stream)
           [::]:6720 (Stream)

Feb 28 17:31:28 SmartHomeNG systemd[1]: Closed KNX Daemon (socket).
Feb 28 17:31:28 SmartHomeNG systemd[1]: Stopping KNX Daemon (socket).
Feb 28 17:31:28 SmartHomeNG systemd[1]: Listening on KNX Daemon (socket).