Unable to find any PTR-records for the specified domain/ip :(
Log
+000
Resolving PTR record of '210.138.0.0'
+1.679
ERRNo PTR record availible DNS server 'ns.lan-do.ne.jp' raised an NotExistentDomain error, while beeing queried for PTR-records on domain '0.0.138.210.in-addr.arpa'.