Unable to find any PTR-records for the specified domain/ip :(
Log
+000
Resolving PTR record of '192.230.237.0'
+258
ERRNo PTR record availible DNS server 'ns2.blackboard.com' raised an NotExistentDomain error, while beeing queried for PTR-records on domain '0.237.230.192.in-addr.arpa'.