Unable to find any PTR-records for the specified domain/ip :(
Log
+000
Resolving PTR record of '54.231.120.0'
+134
ERRNo PTR record availible DNS server 'pdns1.ultradns.net' raised an NotExistentDomain error, while beeing queried for PTR-records on domain '0.120.231.54.in-addr.arpa'.