To find host name from IP you have to ways one is querying DNS and another is witout DNS
while querying DNS you need to us the command prompt. In the Command prompt that appears on the screen, type "nslookup % ipaddress % ", replacing % ipaddress % with the IP address for which you wish to determine the hostname. Underneath the line with the IP address you provided, look for the line labelled "Name" and note the value next to "Name" as the computer's hostname.
if you want to do it without using DNS type "nbtstat -A % ipaddress % " at the command prompt, substituting the IP address for " % ipaddress % ". Read the data and locate the NETBIOS table. Locate a row with the type "UNIQUE" and look for the computer's hostname in the "Name" column for that row.