Unable to find any PTR-records for the specified domain/ip :(
Log
+000
Resolving PTR record of '15.12.72.0'
+617
ERRNo PTR record availible DNS server 'ns5.hp.com' raised an NotExistentDomain error, while beeing queried for PTR-records on domain '0.72.12.15.in-addr.arpa'.