➜  src systemctl list-units x11vnc.service nxserver.service
UNIT             LOAD   ACTIVE SUB     DESCRIPTION                                                                                    
nxserver.service loaded active running NoMachine Server daemon                                                                        
x11vnc.service   loaded active running Start x11vnc at startup.                                                                       

LOAD   = Reflects whether the unit definition was properly loaded.
ACTIVE = The high-level unit activation state, i.e. generalization of SUB.
SUB    = The low-level unit activation state, values depend on unit type.

2 loaded units listed. Pass --all to see loaded but inactive units, too.
To show all installed unit files use 'systemctl list-unit-files'.
➜  src sudo netstat -tulpn | grep -E "(vnc|nxserver)"      
tcp        0      0 0.0.0.0:5900            0.0.0.0:*               LISTEN      30009/x11vnc        
tcp        0      0 127.0.0.1:22173         0.0.0.0:*               LISTEN      1011/nxserver.bin   
tcp6       0      0 :::5900                 :::*                    LISTEN      30009/x11vnc        
udp   214016      0 192.168.1.91:5353       0.0.0.0:*                           1011/nxserver.bin   
udp    48896      0 0.0.0.0:5353            0.0.0.0:*                           1011/nxserver.bin   
➜  src