Unable to find any PTR-records for the specified domain/ip :(
Log
+000
Resolving PTR record of '3.172.9.0'
+229
ERRNo PTR record availible DNS server 'x4.amazonaws.org' raised an NotExistentDomain error, while beeing queried for PTR-records on domain '0.9.172.3.in-addr.arpa'.