Unable to find any PTR-records for the specified domain/ip :(
Log
+000
Resolving PTR record of '199.91.189.0'
+237
ERRNo PTR record availible DNS server 'r.arin.net' raised an NotExistentDomain error, while beeing queried for PTR-records on domain '0.189.91.199.in-addr.arpa'.