Unable to find any PTR-records for the specified domain/ip :(
Log
+000
Resolving PTR record of '2001:728::'
+483
ERRNo PTR record availible DNS server 'auth25.ns.gin.ntt.net' raised an NotExistentDomain error, while beeing queried for PTR-records on domain '0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.2.7.0.1.0.0.2.ip6.arpa'.