Unable to find any PTR-records for the specified domain/ip :(
Log
+000
Resolving PTR record of '18.68.105.0'
+158
ERRNo PTR record availible DNS server 'x1.amazonaws.com' raised an NotExistentDomain error, while beeing queried for PTR-records on domain '0.105.68.18.in-addr.arpa'.