Determining UID logged in @IP_addr ?

There must be a combination or NBTSTAT, ARP and/or PING commands that will tell me who (UID) is logged in at x.x.x.x IP address.
The closest I can get is:
nbtstat -A -n
but that only gives me [00] [03] and [20] results on the NetBIOS machine name. What about some [00] and [03] results on UID?
Alternatively, do you know of any tools to accomplish such?