Unable to find any PTR-records for the specified domain/ip :(
Log
+000
Resolving PTR record of '64.252.72.0'
+357
ERRNo PTR record availible DNS server 'pdns1.ultradns.net' raised an NotExistentDomain error, while beeing queried for PTR-records on domain '0.72.252.64.in-addr.arpa'.