Unable to find any PTR-records for the specified domain/ip :(
Log
+000
Resolving PTR record of '81.20.40.0'
+169
ERRNo PTR record availible DNS server 'ns4.apnic.net' raised an NotExistentDomain error, while beeing queried for PTR-records on domain '0.40.20.81.in-addr.arpa'.