Unable to find any PTR-records for the specified domain/ip :(
Log
+000
Resolving PTR record of '198.251.144.0'
+083
ERRNo PTR record availible DNS server 'x.arin.net' raised an NotExistentDomain error, while beeing queried for PTR-records on domain '0.144.251.198.in-addr.arpa'.