Unable to find any PTR-records for the specified domain/ip :(
Log
+000
Resolving PTR record of '168.100.72.0'
+194
ERRNo PTR record availible DNS server 'ns-687.awsdns-21.net' raised an NotExistentDomain error, while beeing queried for PTR-records on domain '0.72.100.168.in-addr.arpa'.