This protocol will provide you the usernames of the host. You may be able to find this services listed by the port-mapper service like this:
root@kali:~# apt-get install rusers
root@kali:~# rusers -l 192.168.10.1
Sending broadcast for rusersd protocol version 3...
Sending broadcast for rusersd protocol version 2...
tiff potatohead:console Sep 2 13:03 22:03
katykat potatohead:ttyp5 Sep 1 09:35 14
