5.8 rwho

The Unix rwhod service listens on UDP port 513. If found to be accessible, you can query it using the Unix rwho client utility to list current users who are logged into the remote host, as shown:

# rwho 192.168.189.120 jarvis   ttyp0    Jul 17 10:05   (192.168.189.164) dan      ttyp7    Jul 17 13:33   (194.133.50.25) root     ttyp9    Jul 17 16:48   (192.168.189.1)