Unable to find any PTR-records for the specified domain/ip :(
Log
+000
Resolving PTR record of '2600:1f23:4000::'
+261
ERRNo PTR record availible DNS server 'x4.amazonaws.org' raised an NotExistentDomain error, while beeing queried for PTR-records on domain '0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.4.3.2.f.1.0.0.6.2.ip6.arpa'.