Reverse DNS Lookup
This tool will provide you the hostname (ie www.yahoo.com) of the IP address that you enter below.
Results:
Lookup on IPv4 Address: 131.255.9.8
Hostname: ns1.nptelecom.net.br
Hostname: 131-255-9-8.host.icomtelecom.com.br
Hostname: ns2.nptelecom.net.br