79/tcp open finger Linux fingerd – User Enumeration

nmap

nmap is great

if you will find by nmap 79/tcp finger

nmap -n -sV -Pn -p- 192.168.0.102
...
79/tcp    open  finger     Linux fingerd 
...

you can play with this port,

you can check if any user is logged on

finger @192.168.0.102

other options

finger root@192.168.0.102
finger szalek@192.168.0.102
finger user@192.168.0.102